In Europe you can probably use Revolut, they let you generate single-use cards.
Please note however that websites can tell it's a single-use card and refuse to accept it. Most recently Amazon and their related services (Twitch etc.) started refusing them.
There's KOHO for Canadians, still not a proper Privacy.com replacement but you get two Mastercard cards (one physical & one digital) and they are refillable via Interac payments.
When doing trials, I set a few dollars on the card to ensure if they try to do a 1$ transaction to verify the card and I'm good to go. Even if I forget to cancel, the payment won't pass.
Which is not a good look for privacy.com. You have to be either very lazy to not set up the redirect, or use a very cheap service that doesn't allow you to do it.
No, it's just ensuring SSL encryption to their servers at all times. It's the best possible look for a website called privacy.com.
If they allowed http connections, those connections aren't guaranteed to be private (encrypted).