I personally have studied German queer history in the interwar period, so for context I've read up on the political system of the Weimar Republic, censorship and minority rights, and whether the political landscape was actually as liberal as it seems. My area of study is somewhat specific, so some of the examples I'm going to give might be as well. However, I do feel like discussing minority rights can give some insight into the relative liberalism and conservatism of the Weimar republic. It also must be noted that the Weimar republic is a name that was given afterwards, and at the time the country was simply known as Germany, or the German republic. From now on I will refer to the period as the Weimar period, and to the country as Germany.

In German historiography the Weimar period is sometimes seen as a difficult one to study and interpret, not so much because of the period itself but because of what came after that. In the one-party system of the Third Reich the Weimar period was seen as a period of disgrace for Germany and its people, and this view was reinforced in propaganda. The parliament was all in all pretty unstable for the entire short life of the republic. There were numerous parliamentary elections and the government was also reinstated many times. This, in combination with enormous economical difficulties Germany faced, was perfect fuel to the flames for political extremist movements, of which there were also several. All of this has influenced the ways in which people have thought about the Weimar period afterwards. Historical study of the period was not really made widely accessible until after the German reunification in 1990, since many essential documents were buried in the archives of the GDR. During Nazi regime many historians who weren't symphathetic, fled the country and that further skewed the immediate perspective on the Weimar period. On the other hands it is also often idealized; the period was not nearly as liberal and modern as it seems. It was home to a rampant far right movement, and conservatism was deeply rooted in the society and politics.

This question is multi-faceted, and there is no simple answer. The constitution was indeed very modern, and in comparison to many other countries at that time, liberal. All in all the reality was not so simple, because not all political thinking rises from the current systems that are in place. The practice on the other hand was in many cases far from liberal.

Many of the main facets and principals of the Weimar constitution seem quite familiar to a modern reader. Germany was a representational democracy with the president as head of state. President had some power to limit the constitutional rights if need be due to crisis of some sort, but the president was by no means on the level of the Kaiser. Everyone over the age of 20 was allowed to vote and be elected, own property, practice religion freely and assemble. Freedom of opinion and expression was also clearly stated, and state-run education was mandatory for all children. So yes, the main facets of the constitution were for the period modern and liberal, especially in comparison to other European countries at that time. They were clearly onto something good when creating the constitution and the new representational democracy, but the more limiting realities lie elsewhere.

This is where it gets complicated. It's due to these practical things that I don't think the Weimar period can be described as truly liberal, nor truly conservative. The far left and the military were very opposed to the new constitution when it was signed into law by Reichspräsident Ebert in 1919. These realities I'm about to describe reflect how life the state really was, and how the constitution really didn't offer equality for all people living in Germany - and so it cannot be described as liberal.

In spite of freedom of expression stated in the constitution, there was wide-spread practice of censorship. The Weimar period saw a very active pro-censorship movement, and there were censorship boards operating all over the country. Police also supervised potentially pornograhpic publications and minority publications. For example the LGBT community could in principle publish magazines all over the country, but they were still regularly caught in the censorship system. There was a law concerning "Schmutz und Schund", which roughly translates to "filth and garbage", to which LGBT publications among many others were subject to. Not to mention that gender and sexual minorities were subject to policing, and homosexuality was deemed illegal with punishments ranging from fines to imprisonment. Trans people were subject to some legal control as well, even though it was not literally illegal to be trans or to dress gender nonconformingly. It was deemed under "public nuisance" and required a permit from the police department.

On the other hand, these laws were not very strictly enforced all over Germany, even though it existed. For example in Berlin gender and sexual minorities could gather in bars openly and show affection somewhat publicly. Internationally Berlin was seen as a hotspot for free sexuality, art, nightlife and expressing oneself, and there is truth to it. This was not the same for all of Germany, and not all cities, and many conservative voices found the "state" in which Berlin was distasteful and degenerate. Berlin was even back then a big city and pretty different from the rest. On the other hand Berlin was also very poor, and many young people engaged in survival sex work - which has later infuenced how Weimar period Berlin is viewed as a haven for free sexuality. There was very little protection to poor people, and social services catering to poor people were limited.

Despite of freedom of assembly, protests were often reacted to violently by the police. This was especially true to the Communists, but of course far-right movements were subject to some police control as well. One of the more famous violent incidents is the 1929 Blutmai aka Blood May, where the Berlin police attacked the May Day celebration of the local communist group. Consequently 33 communists and some uninvolved civilians were killed by the police. All in all communists seemed to be more frowned upon by the general middle class public than the nazis.

It must also be noted that ethnic minorities had very little to no protection under the Weimar constitution. Germany at the time was still a colonial state, and so called "Völkerschau" or "people exhibits" were very popular throughout Europe at the time. This was also true to Germany. Being a colonial power Germany was built upon racial inequality and white supremacy, and this did continue during the Weimar period. Antisemitism was also alive and well at the time, and not invented by the Nazis at all, despite Jews also enjoying freedom of religion under the constitution.

Women were not really encouraged to work, even though many women did and had always worked. Conservative voices and mainstream magazines enforced the traditional worldview, and for example abortions were still not legal. Women did not hold many positions of power, either, even though they were technically allowed to be elected, own property and study. The ideal role for a woman was still a middle class housewife. Despite the constitute stating everyone's right to equal pay, women were still most of the time paid less.

The many freedoms stated in the Weimar constitution had many practical limitations to them. The society was a product of its time, and while back then the law and constitution certainly was more liberal than in many other countries, it was not always interpreted in a way that might truly be described as inclusive, or even liberal for that matter.