So many bugs in samsung one ui 4.0

[Zaid1924]

Is there a way to go back to one ui 3

My samsung galaxy s21 ultra is hanging while opening certain essential apps like maps etc since i updated my phone. Also facing many other glitches 

[Miatham]

Due to Samsung's policy, you cannot go back to the previous version of android. The bootloader has been locked after Jan security patch. However, you can wipe the cache and do a repair to your apps through recovery mode, it might resolve glitches

[Basso12]

Don't think that's possible, however you may have to wait for the future updates which might include bug fixes.