Hi Lucas !
Thank you for contacting the Microsoft Community!
Regarding your cluster upgrade issue, we also refer to the previous link.:https://learn.microsoft.com/en-us/windows-server/failover-clustering/cluster-operating-system-rolling-upgrade
(1)You need to go from 2016 to 2019, and then from 2019 to 2022. This can ensure that there are no changes to your cluster role.
PS:Don't forget to run the command: Update-ClusterFunctionalLevel
(2)However, if you haven't deployed the SQL AG role yet, I think it's feasible for you to directly upgrade the node systems of the cluster to 2019, and then create a new cluster (of course, you can use the previous cluster name CNO and cluster IP), and deploy the AG role within the new cluster.
In conclusion, both methods are feasible. The steps in Plan Two might be challenging, while Plan One is safer. I wish you all the best!
Best Regards,
Andrew