What had the Russian government to gain from the late 2021 military build up and threatening possible invasion of Ukraine?

I tried to find a clear answer from the media (too many examples to list here, search for Russia-Ukraine conflict in the news), but could not quickly find good, comprehensive answer with non-speculative analysis. Even the typically easy to understand political analysts such as Vitaly Portnikov do not provide a clear answer. Other sources, such as below or in comments, do not provide enough in-depth analysis and/or a clear answer.

REFERENCES:

See, for example, Vitaly Portnikov's videos here: https://www.youtube.com/channel/UCV0ZrOPCKzqx36rRiPHkwFg However, the ones on topic here are somewhat less clear than they could have been.

Is Russia preparing to invade Ukraine? And other questions - BBC News: https://www.bbc.com/news/world-europe-56720589 - on topic, but there is not enough analysis here, mostly facts without synthesis and discussion. Thanks to Jontia for the reference to this useful reference.