If you need anonymity, I suggest a throwaway account like mailinator.com where you can use it when you have to fill out forms that you don’t want to have your normal email address bedause you know they Wil, spam your account.
You pick any name you want, like say kangaroo@mailinator.com, or picklepuke@mailinator.com, whatever you wish, fill out the form where some company requests your email, then go to picklepuke@mailinator.com and you will see the email from the company in the inbox there. You don’t need to sign up either.
They keep the emails for I think 3 days or so, then they autodelete them or you can do so yourself.
From then on, all the spam that the company you had to fill out a form for goes to the mailinator account, not your regular email
One thing though, some companies are wise to throwaway account ts and won’t allow them, but most are unaware it seems