Alright I think I've found out something. This was really annoying me probably because I kinda have this "perfectionist disorder" or something like OCD.
Okay I changed some widgets because Google widget won't stop displaying the weather in place of the date, and removed some of them after I've uninstalled and reinstalled Google keep then realised I mostly use just 3 widgets out of 6 that were previously stacked. Then I noticed that the reloading time was reduced. I think it's that the stacked (or "smart") widgets aren't optimised or Samsung didn't expect that someone would use or stack multiple widgets of the same app or the processor of this phone is not that capable as expected.
Then I remember that this phone is called...... "ULTRA"
