Hi,
Microsoft Monitoring Agent (MMA) is not deprecated. In fact this is the agent that should be used when monitoring VMs/servers via Azure Monitor. As you mention SCOM that one has separate agent called Operations Manager agent. Unintentionally the service of that agent when viewed on Windows is called Microsoft Monitoring agent which could be confusing. Overall Operations Manager agent comes with SCOM and it supported along with the SCOM management server. So as long as your SCOM management server version is supported your Operations Manager agents are also supported.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.