Are there actually any good NFTs? I know a few projects like Bored Ape and M'Lady that had staying power cuz memes, but isn't the ultimate destiny of every NFT to end up worthless?

That really depends on if somewhere like MoMa tries to pick it up. They are legitimate pieces of art history, depending on how well they splash into other media trends. Not all art is good, it simply is. 

A dude taking a dump into tin cans and sealing it with a custom painted label ended up being enough to count as high art, over it being a protest against another artist who did the same thing with time capsuled garbage.