Did you have the work carried out by a Samsung Authorised Engineer in a Samsung Service Centre to ensure your warranty wasn't voided @liamtorrie
Normally I would say go to a Samsung Service Centre as they'll help and they guarantee their work.
You could run a diagnostic via Settings > Battery and Device Care > Diagnostics.
Try > Clear Cache Files from the phone's System Partition Section > https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to insert your earphones or hook upto a powered On Laptop to access the Clear Partition Section. This may help with lag or stutters as this clears the phone of old/unused or broken cache files.There is also a Repair Apps option in the Menu System too.
You can clear the cameras cache via Settings > Apps > Camera > Storage > Clear Cache.
A last resort would be a factory reset and you can send feedback via your Samsung Members app.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
