As much as I understand it, most countries don't want to confiscate the assets because it's probably illegal. You could still do it but so could China then do the same with Western assets.
The most favorable plan is the reparation loan. if you can legally argue that Russia needs to pay for the damage they've done in Ukraine, then you can use those assets. Russia's only way to get those back would be to pay for the damages in Ukraine and since that would be probably even more than those few hundred billions, it would mean that we could indeed use Russia's assets and never pay Russia back for it.
But there's still not a real answer to if and how they will handle those assets to use it for Ukraine.







