I’ve been using email aliases for a few years now, but all spam I get is addressed to my main email (which admittedly is readily available on my website). Seems like no one has sold my email address yet

While the disposable cards might not always work, you can always create a regular virtual card and delete/freeze it afterwards. Not sure if there are any limits tho

Not really the same thing, but Revolut has disposable virtual cards that you can use (but it’s a full-fledged bank).

Some apps like MBWay in Portugal also allow you to create these virtual cards, but it requires a Portuguese bank account.