Transnistria is already basically occupied by Russian military with a friendly pro-Russia government.
Moldovan population without Transnistria is less than 2 million people. Ukraine's pre-war population was 41 million. Ukraine's area is also around 18x the size of Moldova. Similar situation with the Baltic States being relatively tiny both in size and population.
Also it isn't really just Russia is it? China is pretending to be neutral but you can get bet they had a hand in getting North Korea to send troops. If Russia wins in Ukraine you can bet on more open and brazen Chinese support for Russian rearmament as they become less dependent on trade with western countries.
I said earlier in the thread some people are stuck viewing the world through the paradigm of the Iraq War era and the US unipolar moment. But that was 20 years ago and the world was very different then - China's total GDP size had only just overtaken Italy's in 2003. We are already in a multipolar world. Russia having the confidence for all out war with Ukraine would have been unthinkable 20 years ago and the rise of China is the main reason why.
An attack on the Baltics or Moldova, and a Bosnian crisis (probably spreading to Kosovo) manufactured by Putin ally and Republika Srpska President Milorad Dodik is also likely shortly after Russian victory in Ukraine. Baltic states is the least likely of all these and will probably come last, but if NATO reaches a point where Putin feels it is unlikely to enforce article 5 then he will seek to prove that NATO is over as this would finally restore Russian hegemony over Eastern Europe after a 4 decade interregnum.
This won't happen immediately after Russian victory but it won't be more than a decade down the line either. Letting Putin win in Ukraine will not bring peace.