Im wondering what kind of tv to look for?
IMO 4k is useless because the network where I live is bad and 1080p is good enough. I don’t think smart tv functionality is a thing to look for, more like a « what not to look for » criteria.
What other criterions should be taken?
I think at this point you’re only going to find 1080p in a thrift store. If that’s fine with you, you can probably get one for $20-30.