Aliasing and forwarding is not a good solution if you are concerned about law enforcement, because your personal e-mail is still linked with the tracker, just behind an extra hop and in addition you allow someone in between to read your e-mails. You had the answer yourself. Create a completely fresh free e-mail account somewhere, using as minimum a private tab to prevent tracking data to link anything to the account… and if you can get a free e-mail account with IMAP/POP access so that you can use it in an e-mail client to leak less data, do that.

Icreated a new email on proton for tracker and piracy stuff. No need to have it associated with my regular email/persona

I recently started doing this for everything with Simple Login. You can create aliases either ahead of time or configure them to be ad hoc. I went the route of a custom subdomain, but that’s not required.

I create a new email for each new sign up so I immediately know who leaked it. If spam is coming I can close it

If you’re in the States, maybe take a peek at Firefox Relay.