As mentioned in comments already they are both not secure: every new AMD CPU have ARM TrustZone core in it. For ARM I can't tell since there might be SOCs witho

As mentioned in comments already they are both not secure: every new AMD CPU have ARM TrustZone core in it. For ARM I can't tell since there might be SOCs without TrustZone. Best usable hardware is old Intel laptops except you want something like MIPS laptop from Lemote.