Never had a problem with LUKS over a decade of usage. In fact, I'm actually having the opposite issue: I have a drive that is failing and LUKS is still able to

Never had a problem with LUKS over a decade of usage. In fact, I'm actually having the opposite issue: I have a drive that is failing and LUKS is still able to decrypt it by some miracle. > Also, it's slow. Modern CPUs have AES instructions built-in. I would check to make sure you're utilizing them. You should not see any slowdown when using encryption.