I don’t think there’s some kind of “mutual escalation” here. Zelensky made a decision to name a military unit after UPA - it was his decision, made in public. Polish side - in a quite unusual unity - said it’s honoring a military organisation known for mass war crimes on Poles, but I’m not aware of any “ultimatums” it has raised towards Ukraine.
Quite the opposite, Tusk (PM) statements highlighted the strategic alliance between Poland and Ukraine and the need for continued military support, while also criticizing the UPA decision in a very diplomatic language. At the Ukraine’s diplomacy level, there were numerous attempts to deescalate - minister Sybiha, prime minister Svyrydenko all made very reasonable statements.
However, Zelensky seems to run a separate foreign policy in this aspect - and it’s possible he’s even entitled to do so, because Ukraine is a presidential-parliamentary republic unlike Poland, where president’s role is very limited. Or more precisely, it’s limited legally but not in PR terms, unfortunately. He can’t do much legally, but he can cause a lot of harm my mere making statements.
The publication of the PAC-3 donation to Ukraine in my opinion was 100% Russian disintegration operation - they leaked it to right-wing politicians in Poland and the government was forced to respond to that.
Why is Ukrainian president escalating in such a situation is well beyond me, but the fact that his ratings have benefited from this scandal - just as Nawrocki’s, who also runs a separate foreign policy, although mostly on words - suggests that both are simply in electoral campaign mode already and don’t give a shit about foreign relations with “weak” neighbours like Poland. It also suggests there will be even more escalation between the presidents, while our governments will scratch their heads on how to do any damage control in such an absurd situation.