Discovered a minor issue where users couldn't register as a customer.
Here's the fix.
I set up my EasyStore QuickStart package and adding a few plugins I sometime choose between including
CAPTCHA - Invisible reCAPTCHA, and
CAPTCHA - hCaptcha (my preferred captcha)
I enabled and configured hCaptcha and set it as the global default Captcha. Subsequently no matter what I tried I couldn't get the Customer Registration page to appear, it always went to the default 404.
I spent quite a while trying to find the problem.
The answer was in front of me... the 404 page has some extra message about "reCaptcha". I wasn't using reCaptcha so I ignored this. When I did start looking at the Captcha's as a possible cause I discovered the CAPTCHA - Invisible reCAPTCHA plugin was enabled, even though it wasn't set as being used in the Global Config. When I disabled the CAPTCHA - Invisible reCAPTCHA the problem resolved. So there must be some registration related coding somewhere that tries to use CAPTCHA - Invisible reCAPTCHA if it sees it enabled, even though you are using a different captcha (in my case hCaptcha) in Global configuration.