I'd argue that PoMA is more Grimdank than Grimdark tbh. Like yeah the atmosphere and the lore kinda matches up with what the characters are doing but man...
But also it's probably an argument against all Xianxia/Wuxia that is not comedic or purposefully super-serious. In the same story and even sometimes the same scene you can have a tragic backstory moment where some dark **** is revealed, people rip each other's limbs off just to make a point, and then some girl from the bleachers yells "OMG LONG CHEN I LOVE YOU!!!<><><)))"
Probably why I like Aura Clash more tone-wise - anon has an ideal balance between comedy and then transitions smoothly into serious stuff, or makes it a point that there is a tone mismatch.