Putin didn't care about USSR, he actually helped to dissolve USSR and embraced capitalism with his oligarch friends. He started to hate US after US government especially Democrats like Hillary and Obama started to threaten his power by supporting Russian oppositions and sanctioning his oligarch friends' businesses. In 2016 he supported Trump just to sow chaos and undermine people's trust on US election not because he confident Trump will win. I guess he hit the jackpot when Trump proved more incompetent than anyone could imagine.
One of Putin supporter in Quora posted this answer:
Yea the article didnt say hes a secret communist but more so the loss of prestige affected his attitude towards the west in general. Hes a hardcore nationalist Im sure seeing moscow humbled in the 90s did something to him. He's said as much that they ain't going back to them Yeltsin days