underrate
This is a beautiful, underrated film.
Bullying is one of the most underrated and enduring problems in schools.
She is underrated as a coach.

SMART Vocabulary: related words and phrases

Exaggerating & playing down
bloviate
blow something out of proportionidiom
cartoonish
cartoonishly
catastrophize
fulsome
go overboardidiom
inflated
make a mountain out of a molehillidiom
make little of somethingidiom
make much of somethingidiom
make something of something/someone
meal
mildly
minimization
OTT
protest too muchidiom
romanticize
underplay
underrate

underrated | American Dictionary

underrated
adjective
us/ˌʌn·dərˈreɪt̬·əd/
having more importance, value, skill, power, etc., than people recognize:
He is one of Hollywood’s most underrated actors (= He is much better than people think).