It would help to know the error. Are you sure it's upset about the CPUs? Have you tried Compare-VM to see exactly what it doesn't like?
Run the Cluster Validation Wizard to see if it yields clues. The article was written for 2012 era hosts but the only thing that's changed is the depth of the validation checks. Skip the storage checks so that your guests stay online.
If the CPUs are different, then the CPU compatibility setting is not a magic bullet. There's no easy way to know in advance (unless the CPUs are from different manufacturers). Sometimes processors have substantial differences that can't be masked away. The Cluster Validation Wizard should at least warn about this.
If you know that they have the same CPUs and you're certain that it's a CPU problem, then most likely this is due to a mismatch of BIOS or Windows Update levels. I don't know of anything major that's happened recently that makes this likely, though. The fixes for Spectre and Meltdown type exploits required the hosts to be fully patched and power cycled (not just restarted) and then for the guests to fully patched and "power" cycled (not just restarted). Any mismatch across a cluster and Live Migrations will fail. The Cluster Validation Wizard should detect mismatched patch levels but it won't know about power cycle status. However, those fixes were long enough ago that it seems unlikely that anyone would still be encountering problems with them unless something is REALLY out of date.