Bitwarden has a setting for doing exactly this. Create a random email and a random password on the fly during a new service signup
Also possible to create 2-3 fake Personas in app (Name, DOB, address,…) to scatter your online footprint. Fills forms with the right one at button push.
If you are using a password manager, then this shouldn't be too difficult.
It can be a hassle when registering for something in person, though.