Yeah it's just so hard to pin down where the issue is coming from, at one point it was seeming like there were specific issues with libreelec and IA but that now looks to be an unrelated issue.
If someone can say for sure though that their x86 install of libreelec 12.2.1 is working correctly with widevine L1 then it's prob just my setup specifically being borked and I'll just have to do a full reinstall.