Sorry to have to break this to you, but no you can’t. They only allow one alias per third party website. No more. So if you have 2 Instagram accounts, you can only afford 1 Proton Pass / Simple Login alias for one of your accounts. Even if you managed to create more than one alias for the same website, it’s not allowed. I’ve talked about it here and here.
I am saying that that Proton can distinguish the difference between:
A) Creating 5 aliases to email 5 different people who use the same email provider (Gmail).
vs
B) Creating 5 aliases to manage 5 online accounts from the same website (Reddit).
A is allowed. B is not.
If you have 2 Instagram accounts, you can only use a Proton/SL alias for one of them.
The reason I brought up Substack is because there are 2 ways to subscribe to a Substack newsletter. The first is by creating a Substack account and subscribe to other Substacks through your account. This means that every time you log into Substack, you will see all the Substacks you are subscribed to.
The other way is by not creating a Substack account, and just entering your email address every time you find a Substack you like, and you will receive the Substack newsletter directly to your email address.
Both methods require an email address. The difference is, in the 2nd method you don’t have a Substack account, and therefore can use a different alias for every Substack. At least that is my understanding. Someone correct me if I’m wrong.