Liquid Glass made my 13 mini consistently lock up and overheat. Multiple reboots every day. Ludicrously slow screen repaints. It only stopped with the latest version (26.5).
Anecdotal evidence is not proof, and as I’ve seen two people in this thread saying the performance of their iPhone 13s improved after iOS 26, I don’t see how you could concretely attribute any of your issues to Liquid Glass specifically (especially since you say it has been resolved with 26.5 despite Liquid Glass still being present in the os).