Bitwarden can do both automatic email creation and also store the identity(s) and fill them in for you.

So it doesn't need to be a ballache, can be one-click transparent.

Commercial email providers will typically provide some number of aliases aimed at doing this for you.

Proton Mail's a popular provider in Switzerland, for example:

https://proton.me/mail/pricing

Their $3.99 /month service provides 10 aliases.

Their $9.99 /month service provides unlimited aliases.

And will work with a domain you own, so it's not like you're locked to them if you want to move to somewhere else down the line.

Abine (now IronVest) just sells the privacy aspect. They aren't an email provider -- that is, they don't give you an email box -- but provides this "masking" service to forward it to your regular email provider, if you already have email service.

https://ironvest.com/pricing/

Their $39/year service provides 50 aliases.

Their $99/year provides unlimited aliases.

They also do some other stuff like provide masked phone numbers that forward to your real number. They have provided masked, temporary credit card numbers with charge limits and a bogus name and address, so you don't even need to give your real name to someone you purchase something from online (though it looks like that's currently not available, says that they're bringing it back. I have used a masked credit card number from them in the past, so I know that at least some merchants will accept it, though I'd think that it'd tend to trip anti-fraud stuff at merchants, but...shrugs).

That being said, while I think that this sort of thing is a way to reduce the increasing degree of data harvesting -- you can't always choose whether-or-not to use certain services -- I think that if you have the option to choose a product or service that doesn't harvest data on you in the first place, that's really a better option.