Can I install FB 4.7 on win 11?
Windows is usually pretty good at backward compatibility. Give it a try and see if it works!
This might be helpful too: https://web.archive.org/web/20210122145322/http://blogs.adobe.com/flashplayer/2018/02/running-adobe-flash-builder-on-mac-with-java-78.html
You probably can, but I'd ask the question why? 🙂 FlashBuilder is so old and unmaintained it really is worth considering trying something new.
Have been thinking about moving to intellij, but have so much to do that I prefer keep going with FB for the time being, learning something new takes time.
Regarding Air apps on Win 11 see this: https://github.com/airsdk/Adobe-Runtime-Support/issues/1742