Hiho @ChristopherHaws, I was testing this build right now.
Everything works on 1.20.1 - thank you so much 😊

I let you close it, until it's released public.

I haven't had a chance to check if it is working (been super busy with work) but there is a 1.20 build that you can download and try out here: https://github.com/ChristopherHaws/mc-expanded-enderchest/actions/runs/5124650229

If this works, can you publish it on Modrinth please?

Updated versions have been published to curseforge and modrinth. Sorry for the wait, been super busy.