Best practices for updating a Windows Failover cluster / SQL Server Availability Group without using Cluster-Aware Updating

I have set up an SQL Server 2016 Availability Group inside a Domainless Windows Server 2019 Failover Cluster.

Everything runs fine at the moment, but now I am wondering what might happen if cluster nodes are installing new updates at slightly different times. For instance what happens if Server A updates at 3:00 and Server B applies the same set of updates an hour later.

Will the cluster break? Will there be outages or will this only cause the Availability group to stop synchronizing to the secondary node until both servers are again at the same update level? My first test suggest the latter option, but it was just one test...

Apparently the best practice is to use Cluster-Aware Updating, but that only works with Active Directory. Since my cluster runs without any domain, I am wondering what the best practice regarding the installation of new updates is in my scenario.