Sleeper cells? Ukraine heating up so Putin isn't fucking around with a 5th column threat.
2nd gotcha' is they'll leave for the EU. From Russia to the EU East block members, who won't take them.
Watch Germany. Merkel successor was picked. A milktoast same old same old rather than a DeSantis type who was stricter on migration. At the same time the 3rd strongest party, AfD, went all in anti-migrant. 2nd strongest party, SPD, is a Merkel party hand holder.
My guess is Putin is going to exploit that tension.
Figure Putin deports illegals (sleepers), who will seek asylum at EU border (Poland, Hungary) who then have to take them, according to EU rules, but probably won't. Same shit as happening in Greece if they do.