A new 5.15.1 version of QtWebengine is in the [build] repo, this is a start of moving (one of the last) away from python2 for any chromium based.
It did build successfully after adjusting the Freebsd patches. Relevant commit:
This move is discussed on the KDE Distributions ML:
Expect regular rebuilds, since it still needs a lot of fixing to work with JS (thus won't move to all users as is now).
Falkon still works with sites tested, just any JS fails to load.
Not works correct in many sites, one of https://www.transfermarkt.de/ wait to load and scroll down. Pictures are not update (some ajax, js or code after page loads it does not work) But that's exactly the problem with others too.
QtWebengine build on python3 with Freebsd patches has been removed. Seems no further work is done to complete this python3 transition, current state is not usable enough to move to all users--[main] repo.