LXQt uses Xorg/X11
Lubuntu does not support LWQt
Links that maybe useful are
The LXQt found in all 22.04 media currently is the initial release we provided; and the Backports PPA provides a much later release as found in Lubuntu 22.10.
Mention was made for alternate media possibly being created (if demand was high enough), but that media would be unofficial as official Ubuntu media cannot include packages from PPAs. It’d be the same except the PPA was already enabled, instead of needing your to install official media then add the PPA.
Links on backports for jammy - https://lubuntu.me/jammy-backports-22-04-1/
Better performance?
This is less factual, but in most of my testing/usage I’ve found it pretty much the same.
As software gains more features, it tends to grow thus the resources required to run it well seem to grow as well. This isn’t a problem for most of us, as we use somewhat modern hardware, and update it every few years, but not everyone does that.
On my lowest resource hardware, I’ve found 20.04 a little faster on occasion and I wonder if the unsnapped version of chromium/firefox is part of it; but that would only be part of the picture I’m convinced. Personally I believe the better security offered by the later release makes it worth it, however my weakest device is running 20.04 still.
lenovo thinkpad sl510 (c2d-t6570, 2gb ram, i915)
Whilst that’s not my oldest device; I consider it my weakest (amd64) largely because of the low RAM. Also note much of the time the difference in speed when it’s been used to run 22.04 it feels equal in speed, but on occasion I have noted that it appears slower so I suspect it is marginally. This is subjective opinion only and I do not use stop-watches unless I have problems. I still consider the security benefits worth it (but I rarely use that device anyway, esp. online, so security doesn’t concern me with it).
If you’re happy with Lubuntu 20.04, I’d feel comfortable still using it whilst it’s still supported by us, which is until late April 2023.