My advice is to put the phone in Safe Mode which disables your downloaded apps and leaves the stock ones working and then see what happens.
If it improves then one or more of your apps is causing this or a theme or 3rd party launcher if relevant.
Come out if Safe Mode and start deleting your most recent apps one at a time until it stops.
If this continues in Safe Mode and all your systems are up to date and your signal from your network is strong then try a back up and factory reset as a very last resort.
A Samsung Experience Store or Samsung Service Centre can run a diagnostic test on the phone.
Daily Driver > Samsung Galaxy s²⁵ Ultra 512Gb ~ Titanium Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "
