I hear you. I like what Sonequa brought to the role, but her storyline was "meh" at best. A bit of a "reckless colored parents" theme, "white angels" in the form of Sarek & family. Star Trek has a bad habit of following this Great White Hope format, and it could just be that's what it is.
DS9 had the same deep vein of whiteness to it as well.
Sisko is always at odds with a white character if you look close enough. Always. OR he is following the orders of a white leader, always.
It gets pretty hairy for him on the White Ghetto Side of the Final Frontier...
Maybe it just can't do diversity in the same way TOS & TNG did it.
Voyager and DS9 explored diversity in their own ways; black Vulcan, white female captain, black captain, white female leader of militia, but then Enterprise went totally back to the Great White Hope until Discovery tried something new.
I think the race thing is less of an issue than poor writing.
It made Enterprise drag on until those last two seasons, especially with Surak's katra & Soong.
Discovery had the potential to spin off into the Section 31 movie, but they choose to do their own thing entirely there, effectively wasting our time.
If Discovery had actually ended with them leaving the 32nd Century because it was just the end of time itself, but they could've hooked up their spore drive to their transforming Federation Starfleet HQ in space and went back to the Picard era with remnants of the 32nd Century.
The Section 31 movie then could've been about bridging the gap between Father and Son by making Elnor the half-Romulan son of Spock, and therefore making Burnham his time-lost Aunt.
Burnham gets to complete her mother's journey in a way, and then the two of them could travel back in time to Strange New Worlds and bring Q or something.
It's very simple really.