Realised that ae2wtlib-15.2.1 was causing a crash upon "loading bootstrap resources". Removed all the mods apart from appliedenergistics2-forge-15.0.15 and it still crashed.
Forge Version: 1.20.1-47.1.84
Log: https://mclo.gs/Di4fgm4

Mod ID: 'ae2', Requested by: 'ae2wtlib', Expected range: '[15.0.12,16.0.0)', Actual version: '[MISSING]'
Mod ID: 'cloth_config', Requested by: 'ae2wtlib', Expected range: '*', Actual version: '[MISSING]'
Mod ID: 'architectury', Requested by: 'ae2wtlib', Expected range: '*', Actual version: '[MISSING]'
Mod ID: 'curios', Requested by: 'ae2wtlib', Expected range: ' *', Actual version: '[MISSING]'

you need cloth_config architectury and curios
it also seems you don't have appliedenergistics2 installed

Right, after installing Curios the mod works perfectly👍.

I don't know why AE2 is missing since it was in the mods folder.