(Yes I know that nations did not technically exist but I’m using the word for lack of a better one)

Some examples of the rise in status would be the duchy of Bohemia within the Holy Roman Empire transitioning into the kingdom of Bohemia, and the county of Lancaster within England turning into a duchy.

A famous case of a lower title not claiming itself as a kingdom would be the Grand Duchy of Lithuania. Now as for Lithuania I do know that they were a kingdom only for a little while, but I can’t really find the reason why they went back to the status of a (Grand) duchy, and on top of that, they were massive, if not bigger than the Holy Roman Empire itself. There’s also the county of Toulouse that was much bigger than their fellow ducal vassals of the French crown, and yet they never became a duchy?

So to restate my question in a broader sense, what steps did a nation take to increase/receive its status, was it typically easy or hard to increase its status in such a way, and were there any benefits and/or downsides/ restrictions to increasing your title?

P.S. You can interpret this as a general “how did titles work” in general, so if you want to answer as such, then go ahead.

P.P.S. You can also answer all the specific examples i provided since I understand that this question may be a little broad.