It was only a matter of time but Ghex also fell prey to the GTK4 madness.
The usability has decreased. More mouseclicks and keystrokes needed to do the same.
It crashes or hangs and is, ofcourse, butt ugly.
It also overwrites files without warning 
I found a good, reliable and stable replacement. It even looks better 
It is called 'dhex'
Yeah, I never upgraded past GHex 3.41.1 (GTK 3). Pin it down!
(I'm not using Ubuntu - it's a rolling release one - but at least the package was well built to continue working on its own, natively, since 2021)
Luke, you're great ! 
Thanks 
wget 'https://archive.ubuntu.com/ubuntu/pool/universe/g/ghex/libgtkhex-3-0_3.8.1-1ubuntu2_amd64.deb'
wget 'https://archive.ubuntu.com/ubuntu/pool/universe/g/ghex/ghex_3.41.1-1_amd64.deb'
sudo apt install ./libgtkhex-3-0_3.8.1-1ubuntu2_amd64.deb
sudo apt install ./ghex_3.41.1-1_amd64.deb
echo ghex hold | sudo dpkg --set-selections
echo libgtkhex-3-0 hold | sudo dpkg --set-selections
And thank <deity of choice>, no dependency hell 