So, let’s say you created a ProtonMail account entirely on your Tor Browser through the Tor mirror the entire time and then also signed up to SimpleLogin/AnonAddy to have an e-mail alias/cloak for each account that you have (for example, say you have make an Reddit account and you go and create an alias for the Reddit account and that alias will be used ONLY for that account and nothing else)
Would it be a bad idea to make aliases and use them for stuff tied to your personal identity (such as banks or stuff you’ve previously used payment options tied to your name etc) or it wouldn’t matter?
Aliases are always recommended over your main email address.
You can have a few email addresses (1 protonmail for personal stuff, 1 protonmail for anonymous/private accounts, etc) and then have a alias account for your personal email and an alias account for your anonymous/private email, etc. This way if the alias service you use gets comprimised, it will not link your personal accounts to your private/anonymous accounts.