For users of Gmail, I can confirm this works and you can even set it up so that address+nameofshop goes to a folder called “nameofshop.”

You can also apparently add a dot anywhere before @gmail.com and still receive the email. I haven’t tried this one, but the last time I mentioned this someone said it was part of the email standard, so presumably it works.

I don’t know of tricks specifically of this vein for proton mail, but I do know you can setup a catch-all address so, for example, something addressed to invalidaddress@domain.com goes instead to spam@domain.com.

I’ve not tried SimpleLogin, but apparently it offers similar functionality.