I don't see 'Dolly' until May 18, so I don't yet have an opinion of this production. But I'm struck by the fact that yours is one of only two negative reviews I've read so far.
The other one is Terry Teachout's in the WSJ, which is surprisingly harsh. See link below.
The tone of your review is sadly honest rather than harsh, but a marked contrast to the general raves.
I don't know whose reviews are most accurate, but maybe we can't rule out the possibility that the critics -- like the rest of us -- love Bette so much that they can't bear to say anything critical about her performance.