Lubuntu 22.04 LTS hasn’t been released yet (it’s still Lubuntu jammy or the development release)
It’s currently in beta and very soon will hit RC (Release Candidate) status, thus is best found on the ISO QA (Quality Assurance tracker - http://iso.qa.ubuntu.com/qatracker/milestones/429/builds
Please refer to Lubuntu Jammy Jellyfish (22.04) Beta testing Week as that’s currently the best place I can probably suggest.