Hide and update old names
This is an extension for hiding and replacing any visible instances of your deadname while browsing the internet. This includes changing names on email and other accounts, swapping within email addresses, and hiding autofilled input fields for account logins that may use an old usernames or emails.
To configure, right click the extension icon and go to the options page. There, you can input any number of name substitutions you'd like to make, and configure which websites are filtered. As a general rule for the config, you can be very non-specific with capitalization etc, and just add more rows for specific cases. The most specific rules will be applied first!
The extension icon works as a way to quickly see the config for a website you're browsing, and you can click it to toggle filtering entirely on or off.