“Moldavia is not a NATO member as you know.”
Yes, which is why he would attack it before Poland. He’s already got a Russian-language enclave there that he’s got agents ginning up into secessionist fervor.
“But Putin would have to be crazy to attack a NATO member.”
If he smells weakness, which he will if Europe and the US decide to let him take Ukraine, and does NOT start ramping up industrial production of military equipment and supplies, which is what is needed to aid Ukraine and at the same time keep their own a@@es covered, he will go after Moldavia. Not a NATO country, after all. If he gets to eat Moldavia, then he concludes that NATO has no will to fight. And then, in his world view, he would have to be crazy NOT to attack a NATO country, and get back all the components of the old Czarist empire, because the West is a paper tiger.
On the other side, if Russia depletes its assets going after Ukraine with full-throated western support, China will smell weakness, and condition its further “help” of Russia on the return of Siberia, or simply retake Siberia if Russia is weakened enough, which was a part of Chinese empire until a few hundred years ago, and also refrain from taking Taiwan for the nonce, in case Trump wins, or to help keep him from winning, so that Xi will have an easier time taking Taiwan from idiot Dems. After the election, Xi might have more flexibility, or not.
It's possible that Putin will attack Moldova, and that would be bad for both Moldova and Russia, and indirectly the whole world. My guess is Putin knows that, but Russian politics (oligarchs) might convince him to go ahead.
Such a move would require very long supply lines, and unless the map of Ukraine changes dramatically, those lines would have to be partly over water. Therefore I don't think Russia under any relatively sane leader would do it while Ukraine is standing. NATO/US very likely would use greater numbers of, and more advanced, aircraft. Anti-Russia sentiment in the US and Europe would increase. I hope he, or any Russian head of state, chooses a wiser path.