Cosleeping + side sleeping makes me blame my mattress more than my side sleeper pillow

I adjust all night. Arms, shoulders, baby, space — repeat. A side sleeper pillow helps alignment, sure. But once I wake up, everything still feels crowded and uneven. At this point I can’t tell if the pillow is wrong or if the mattress just isn’t built for two bodies shifting all night. Anyone else feel like cosleeping exposes mattress issues you never noticed before?