There's a reason why tactical nuke research has been so scary. Even with tactical nukes being used, MAD is still MAD. The entire world is kinda hostage to a specific level of escalation. I just hope and pray that Russian citizens have each identified a pro-Putin local authority figure that they will publicly string up as soon as any nuke is used against Ukraine. I'm probably wrong, but the only possible route to sanity is if the citizenry literally murders the government in a groundswell of rebellion and prays that wealthier nations invest aggressively in the peace dividend. But these explosions of rebellion are a bit like dancing shirtless guy. It's gotta be done, but the 3rd participant is just as important as the first.
As it is, small acts of vandalism against wealthy pro-war Russians would reduce their morale without actually damaging the economy in ways that make it harder for Russians to feed themselves.