The phone will quite possibly be indexing itself after the update and should settle down.
Please try a soft reboot by turning your phone Off and On and please do follow @LiquidSnake excellent tip of clearing the phone's system files cache if necessary.
This is performed via Clear your phone's System Cache Files by turning your phone Off and then from a set series of button presses go into the phone's System Files and clear the cache. No information is lost this way. You may need to insert your headphones or hook upto a computer with your data cable to get to this menu on the phone. https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/
I wish you all the best with this.
Current Phone > Samsung Z Fold³ 5G.