I assume yiu have plenty of onboard storage and some ram is free @Aitar
Sometimes a firmware update leaves redundant files behind which can cause hiccups.
First try shutting the phone down and go through the specified button presses to enter the phones file system and clear the system cache.
If no joy then Back-Up and Factory Reset.
Current Phone ~
Samsung Note 20 Ultra 5G SM-N9860_256Gb SnapDragon 865+
Samsung One Ui 3.0/ Android 11.
Following what @BandOfBrothers said, press and hold the Power, Home and Volume Up buttons until your phone vibrates, you can then release all buttons, once recovery mode has popped up use the Volume buttons to scroll to 'Wipe Cache Partition' and press Power to select.
Then scroll to 'Reboot System Now'.