After updating to One UI 3, my S10+ now stutters when swiping to close apps. Screen response is slower. And more RAM memory is in use at all times.
On another note, the location of the Power Off and Settings icons in the Quick Panel are lifted all the way up which defies the purpose of one hand usage. I thought it was cool to lower them with One UI 2 so they can be easily reached.
I think you have to wipe the catch partitions if you face any issues after any major updat.
Switch of your device. Press and hold Power key + Volume Up key. When you phone starts to turn on release all the keys. Now you are in Recovery Mode. - Use the Volume key to navigate down to highlight Wipe Catch Partitions. - Select by pressing Power key. - Select Reboot Device by pressing Power key. - Your phone will restart. Done. thanks to the member Mr. Basselk who wrote those steps for same case.