Gantry, which powers all the themes, is presently only Joomla 4 certified. You can follow it's development here where Joomla version support will be updated:
github.com/gantry/gantry5/blob/develop/CHANGELOG.md
SEARCH the forum first! These boards are rich in knowledge and vast in topics. This includes searching just the 'Solved' forums, using Google, and using ChatGPT