Should i charge my 89% battery health iphone xs over night and what will happed if i do it?

Set the battery for Optimized Battery Charging and connect the phone to the power adapter and leave it connected all night.....every night.

This will not improve the current Battery Health, but it may help prolong the life of the battery long term.

89% battery health in my opinion is still pretty decent for an old phone like the XR and I would continue using it normally for now.