I would also like to chime in that I am having the same problem.
I am upgrading from WooCommerce 4.3.3 to 4.4.1 when I get this problem that creates the error that makes access to the website not possible,
I have switched to the default Twenty Twenty theme and is still getting the problem. I have since loaded up a backup from my website host cpanel.
So now my website is functional, but I am not able to update to WooCommerce 4.4.1