Pretty much, The Hordes causes a rendering overlay crash on full load after startup with EMF installed alongside it. I'm using Forge v47.2.0 on Minecraft 1.20.1 most recent version of both mods for Forge 1.20.1 which is 1.3.0a for The Hordes and 1.2.1 for EMF. I reported this same issue on their github too.

Crash Report: https://mclo.gs/voUGsy0
latest.log: https://mclo.gs/V0oQXDA

Should be fixed in 1.20.1-1.3.2 let me know if it isn't for you.