If you want latest and not LTS,
You can just add the KDE Qt repositories to get those.
After years of using just what is in the OSS, this past year I’ve been running LXQt with those Qt repositories and haven’t had a problem. LXQt Users should know that LXQt uses the same Qt framework maintained by KDE.
You misunderstood though, because it was not clear enough what I was referring to. I was disappointed in the sense of Qt company, I like LTS releases of Qt for FOSS development and long term stable distros.