In Soviet Union, the rock genre was for a very long time existing underground due to the inability of artists to be properly published.
Only starting with the 1980s could the artists finally publish their songs officially. And even then Soviet government put a lot of measures to prohibit rock music in the country.
This resulted in the appearance of many beloved bands and artists, like
- Kino (tl. Cinema),
- DDT,
- Aria,
- Chaif,
- Grazhdanskaya Oborona (tl. Civil Defense),
- Mashina Vremeni (tl. Time machine),
- Sektor Gaza (tl. Gas Sector)
- Korol i Shut (tl. King and Jester)
- And many others
The history of Russian rock is actually quite fascinating. It was inspired by bard songs and often touched darker subjects as well as being satirical and judgmental of Soviet government.
Due to that, some artists, like Yegor Letov from Grazhdanskaya Oborona and Yuri Shevchuk from DDT, had troubles with KGB (Soviet FBI).
Nowadays, rock artists are still being persecuted for their views. For example, DDT is de facto prohibited from performing in Russia.
Negotiations happen when one or, more likely, two sides don't see a way to improve their positions with military force.
The rumors you're speaking of are a direct consequence of Russia being an autocracy. When you have a country whose ruler doesn't leave on their own (a dictator), people start speculating on when he's going to die. These rumors have been going around for about a decade, I believe, and are pretty much meaningless.
Now, about "securing a legacy." I think it's much more trivial than that. Invading Ukraine was a good way to secure presidency for the next 1-2 terms and to eradicate opposition within the country. If that's the case, then, in a sense, he got what he wanted, although he likely also expected the war to be short and victorious (judging by the state media narrative at the time). That didn't happen. And now there are other issues at hand for him.