it'll never be so obvious that NATO can declare it as an attack

you've seen the playbook in ukraine twice now

there will be an russian speaking minority in estonia/lithuania/... that will that rebel against anti russian oppression, guerilla warfare against the authorities, then they'll hold an rigged referendum, then a decade later the Russian government will formally annex what they've effectively controlled for years

he won't send tanks across the border that will trigger Article 5

Eh but Wagner is not the Russian army, right? They are an "independent contractor" after all. And Russian speaking minorities may "suddenly" decide to rebel. And NATO may be not so eager to activate article 5 since they are not suicidal too.

Long story short I am not sure NATO Eastern Europe is protected 100%. Luckily for now Putin cannot afford another front but there is already some saber rattling between Belarus and Poland and Wagner is in Belarus.