There had been issues when secondary database replica was made primary (Always on High Availability for SQL Server 2017 with SharePoint 2019)
Saving a list form takes long time.
Workflows get canceled or takes long time and so on
After the windows update on Primary Replica, the server is restarted. During this process, availability group went offline and secondary which was acting as primary is disconnected. The service was down for few minutes (primary replica restart time).
Failover shows everything fine but when primary was shutdown, secondary stopped working.