I’m so flat

On both my student model and professional model bass (both Selmars), I am super flat, my open G is 17 cents flat while my G above staff is around 5-8 cents flat.

Oddly though, my right hand notes are in tune to sharp. And my right hand register key notes especially,( B-D) are sharp, with B and C being super sharp.
Besides that, my notes are flat.

Idk what to do as when I try to tighten my embouchure and “bite”, it is still flat, it only gets in tune with when I use a bit less air.

Advice?