It’s not Thunderbird, but I do this in Fastmail (web or app) using their “masked email” feature. Replies come from the same alias created uniquely for my Netflix account.
https://www.fastmail.help/hc/en-us/articles/4406536368911-Ma...
https://www.fastmail.help/hc/en-us/articles/4406536368911-Ma...
If you have a sending identity that matches with the address the email was received, on the app and webui it will reply from that address.
Disclaimer: I work at Fastmail, but not on the webui or app.
Uh. Neat, I’ve been adding aliases individually as I needed them.