Dephysicalizing
keep static and dephysicalize what players don't touch or need collision with; dephysicalizing cosmetic elements improves performance.
FOR EXMAPLE
if you got effects like rain, sparkles, fog, etc., disable collision for 'em.
background objects out of reach, like books or untouched ceilings, should be dephysicalized too. game knows hitbox not needed, visuals stay intact.