I own my email domain, and I register for each service with a different address. For example, flightaware-20240817@mydomain.net. This way, I know where my email addresses leak from.
And many mail hosting services let you assign a catch-all, which allows you to simply use anything@mydomain.com to get the same result.
Big companies do this. I have signed up for things using a +filter email address, only to receive the emails from that company that is signed up to get at my plane address, without the +filter part.
Even if you can enter it, various backends in the same company might not handle it correctly and you enter up with an half-working account that their customer support (if they even have that...) cannot solve. Been there, tried that...
Personally I have - as the separator (not on gmail or similar). If you have to give you email on the phone it can cause lengthy discussions why their company name appears in my email address..
I haven't had issues with it in many years.
Okay. So now you, individually, may be able to attribute some sort of responsibility in some sort of civil action.
Penalties that companies care about aren’t going to be built around some very non-standard individual’s ability to maybe, sometimes, attribute blame.
Plus, the real damaging stuff wont have anything to do with your email addresses.