Will I be banned for going onto the official realm with EasyAntiCheat turned off?

it really makes my system slower and I just want to have better performance.

Not sure if you’ll be banned, but of course you’ll not play with others
If there’s a problem with EAC the game put you into an “untrusted” game (it was like that, not sure), and you can play only with others untrusted, not with EAC “trusted” (normal) people.

Why not join the Fatshark Discord https://discord.gg/K6gyMpu