Considering a single levitating archer with a +1 longbow can grind it down to zero over time, I'd say so, yeah.It's dishing out an average--average--of 148 hp every round, just on its own turn (so not counting legendary actions or swallowed creatures). It's immune to half the world, and it has 676 hit points.
I admit, it feels odd not to have the regeneration, but holy crap, does it really need it?!
Definitely going to house-rule a thrown boulder attack.