Apple Watch 9 keeps on asking for code to unlock

I am using the current version 10.5 and for some reason my watch keeps on locking itself ever so often which is very annoying and useless. The strap is tight around my wrist and I have no tattoos.

I set back the whole watch, connecting it via back-up - still same issues.

I have set back whole watch - pairing it as new watch - still same issues.

I cannot untick passcodes as I am using it to pay for things and if ticked off, cannot pay for anything anymore.

Does anyone have a clue?

I presume it has to do with the latest or the one before last update, because befoe it worked fine and had no issues.

Thanks Kathy