dstke
Wouldn't you know it, after struggling for days to figure this out then finally reaching out, I went back to keep looking and found the missing setting : Settings - Apps - Pleco, scroll down past the usual permissions to special permissions and enable 'allow to appear over other apps (or something to that effect.
Unrelated to Pleco, it's tough using a second profile to isolate the Chinese apps especially sharing photos, my go to app for this is Signal which only works on one profile at a time.