Because the Russians have invested in the right
I think by Russians the Russian state have meddled enough to cause destabilisation abroad, but yeah that has cost money/ been an investment for them, and one which pays dividends or they wouldn't do it. They will continue to do this no matter who is in power, this is the long game for them. Pointless appeasing the Russian state, as they are never going to be on our side or the US side, dems or republicans, certainly not long term.
But, by Russians, this could mean the oligarchs too, and they want it over, as the war is bad for their bottom line, as well as having assets frozen etc, and there are two ways to solve it for them.
A: Convince Putin to give up and go home, and they seemingly have been laying pressure on with this, eventually that pressure will collapse Putin. Difficult to say on timeframes though, for a Putin or full system collapse, depends how much support Ukraine gets, but it's not going to dry up, and they will fight until they can't fight no more.
B: Give back handers to leaders and vocal members of foreign nations, to try and get them to change party/ national policy and change world opinion (unlikely in the sane world) which enables Russia to keep Ukraine.
The weak oligarchs will push for B, and it won't get them very far, the stronger ones will still push for A, and that's only a matter of time and money.
Problem for B is that won't work in the UK as labour are now in charge, and far less susceptible to back handers. I know Starmer likes a Taylor Swift ticket (big deal), but he's not going to be receiving and/ or declaring a free new yacht from some rich Russian etc. The Tories might, but they're not in power, and won't be when Trump's term ends.
As much as Trump might want B, Ukraine doesn't want B and they have the most say. The EU don't want B either, and neither should/ does the UK.
Now is not the time to be soft with Trump or Russia etc, and I don't expect they will be. I think the UK and EU will play nice to a degree, but will ultimately just try and bide time until Trump's crawled back in his hole.