Three years on and Ukraine is still holding its own. There's no reason this couldn't become Russia's Afghanistan 2.0.
Moreover, Ukraine's rules of engagement have been severely limited. They've been unable to strike airfields inside Russia even though they have the capacity to do so.
It's really not holding its own. The military situation is dire. Budanov accidentally let slip that they can keep going for another 6 months...1 month ago. That's probably about when a catastrophic line collapse will occur, if not sooner.
It's unlikely to become another Afghanistan because A) it does not have Afghanistan's superlative geography for hit and run attacks on supply chains and B) coz this war burned through Ukraine's best troops such that now mostly all they have left are TCC-kidnapped soldiers who would rather submit to Russia than fight.
Moreover, Ukraine's rules of engagement have been severely limited. They've been unable to strike airfields inside Russia even though they have the capacity to do so.