If you want to just test it; personally I’d just write a copy to thumb-drive & test it live without install.
Currently we don’t have LXQt 1.0.0 yet in jammy as I mentioned here but discussions have already taken place on how it’ll get into our jammy repository.
When it hits our repository and is available for QA-testing easily, I’m likely to use it as a reason to push Lubuntu QA-testing, and use a recent article by our most recent Lubuntu member (when I read it; that’s how I decided I’d make use of it)