Firefox does have the ability (in their store) to download old extension versions and also to turn off auto-updates. You can do this in your browser if you wish, but do remember to turn it back on at some point because Bitwarden does have limits preventing old extensions from logging in and downloading ones vault.
However, there are also good things added in 2025.11, so you might also consider implementing one of the work arounds in the staff-notice at the very top of the conversation, before the first post.
Please discuss autofill over on this other thread, so that we are not repeating our collective selves and are not causing confusion by discussing two things at once.