Groza is in a very similar vein to "Suvurov"/Rezun's "Icebreaker" hypothesis, which is pretty much pure fiction. /u/Georgy_K_Zhukov has written several good answers to questions on this topic before:

1. How credible are the claims that the Soviets were actively planning to attack Nazi Germany, except the Germans struck first?
2. Are there factual rebuttals to Viktor Suvorov's Icebreaker?
3. Is there documented evidence that Stalin was planning and preparing to invade Nazi Germany in 1942-1943?

The ten-cent version is that, despite the conspiratorial allure of these theories and the factual accuracy of individual supporting points raised by writers like Bunich and Rezun, they're bunk.^(†) Everything we know about the military preparedness of the Red Army in 1941, Stalin's risk calculations, and the mindset of senior Soviet officials indicates that a Soviet attack in 1941 was very unlikely. 1942 or 43 - quite possible, but we cannot know. I would highly recommend starting with a copy of Glantz's Stumbling Colossus (which is not so niche that you'll have trouble finding a library copy, if you would prefer not to buy one). David Glantz is really the granddaddy of English-language Soviet military scholarship, and Stumbling Colossus is one of the works that cemented that reputation for him. It's an extremely detailed breakdown of the Red Army's readiness, troop numbers, and supply situation during the 6 months leading up to Barbarossa, and quite convincingly demonstrates that the Soviets were in no position to be launching a surprise attack. Perhaps continue with Gorodetsky's Grand Delusion, which is a diplomatic history of German-Soviet relations during the years preceding the war. Gorodetsky focuses in particular on the political maneuvering in the Balkans and the role played by Stalin's distrust of Great Britain in blinding him to the nature of the German threat. I have some reservations about parts of Gorodetsky's argument - for instance, he really underplays the role of Nazi racial ideology in Hitler's decision to invade the Soviets - but it is definitely a worthwhile companion to Glantz's laser-focus on military matters.

Teddy Uldrick's paper "The Icebreaker Controversy: Did Stalin Plan to Attack Hitler?", published in "Slavic Review", Vol. 58, No. 3 (Autumn, 1999), is a quick, tidy look at the matter as well. It's available through JSTOR, which I believe still offers free accounts with limited (6 articles/month) access. Your school or local library should also be able to get you access. There's a quote from this paper, which Zhukov also has in one of the posts I linked above, which serves as a solid summary:

Whatever the attraction of the Icebreaker theory, at this stage in the debate some issues are now clear and others still need to be resolved. First, we know for certain that Hitler did not fear a Soviet attack and that Operation Barbarossa was in no way a preemptive strike. The German assault on the USSR was central to Hitler's conception of race war as the theme of modern history. Second, the weight of available evidence does not support the charge that Stalin engineered World War II and had been plotting to do so for a long time, in order to spread communist revolution or Soviet imperialism. Suvorov's contention to the contrary is, to put it most generously, not proven. The currently available evidence suggests that Stalin was not preparing to launch a war of conquest in the summer of 1941, though some of his generals entertained the idea of a limited preemptive strike against the menacing buildup of German troops across the border. It is also true that Soviet military doctrine never envisioned fighting on the defensive for very long against an aggressor, but instead anticipated quickly blunting the enemy attack and then rapidly moving to offensive warfare in order to carry the battle onto enemy territory. Finally, it seems entirely possible, even likely, that at some point in the future, when military preparations had been completed, Stalin would have entered the war against the Third Reich. Ideological considerations aside, he would have done so for the same national security and balance of power concerns that impelled Franklin Roosevelt to oppose Nazi expansionism. German hegemony in Europe was an even worse prospect for Soviet Russia than for the United States. This latter topic—Stalin's perceptions and plans in the face of a consolidated Nazi empire from the Atlantic to the Soviet border—remains an important field for new research.

I recognize that this post has mostly focused on "Suvurov"/Rezun's Icebreaker claims, but those are sort of the most famous and well-rebutted, and are the origin point for similar post-Soviet anti-Stalin revisionist work like Bunich. Therefore, the answers should largely map to Bunich et alia.

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† Anecdotally from persons who worked in the US Army's Soviet Army Studies Office and the UK's Soviet Studies Research Centre at RMA Sandhurst in the 80s, Rezun was essentially a con artist and an obvious fraud. He was a defector and was paid quite handsomely by the CIA for his information on the modern Soviet army, but this info was generally found to be quite poor after the fact as well.