Mask your email services are very handy - here's two you might not have tried both Open Source
Anonymous Email Forwarding
Protect your real email address using email aliases using Addy
https://github.com/anonaddy/anonaddy
Addy is awesome price wise for free you get
Unlimited Standard Aliases
10 Active Shared Domain Aliases
1 Recipient (real email address)
2 Available Alias Domains
10MB Monthly Bandwidth Limit
Then more features if you pay
2nd is Email Masker an open-source browser extension that helps you generate and use masked email addresses for your online accounts using Quick Aliases powered by Skiff Mail.
https://github.com/irazasyed/email-masker
Browser extensions for all chromium based browsers & Firefox Add-On available
https://chromewebstore.google.com/detail/email-masker/oedhkcdedcfloepkpacoocblokifkgjf
And Android you can use simple-login app(which is my preferred option)
Simple login also has browser extensions and android app & is open source also
@corlin yeah simple-login 👍 is powered by proton
Although you can use it with other email services beside protonmail & has an iOS app also which I forgot to mention - even the 10 aliases with free version is good if your using them just for one off sign-ups to get access to some sites then deleting the account and that alias keeps you within the 10 limit - handy indeed