What word is the positive equivalent of flattery?
Consider accolade
strong praise or approval; acclaim
Collins
It tends to be used in more formal settings and is usually reserved for high praise.
A formal term, encomium carries the connotation you are referring to:
- glowing and warmly enthusiastic praise; also : an expression of this.
(M-W)
A eulogy involves commending the character and services of a person, or the qualities of a thing. Although eulogies are most commonly in honour of a dead person, they may be said (even 'sung') to commend, extol, and praise the achievements of living individuals. (OED)
How about a dithyramb? (rare in English but more common in French, especially the adjective, dithyrambique, English dithyrambic)
Merriam-Webster Dictionary defines it as:
a usually short poem in an inspired wild irregular strain
a statement or writing in an exalted or enthusiastic vein
example sentence: a tongue-in-cheek dithyramb of the chocolate chip cookie
The idea is that the speaker or writer is so enthusiastic about the thing or person they are singing the praise of that they get carried away, they wax lyrical; but there is no idea of flattery, no hypocrisy involved.