In general: In infra mode you will miss JVM metrics and service level, but general process metrics and tecnology specific metrics (with extension)you can get with infa-only mode.
Yes, it is possible, but you will miss instrumentation on EleasticSearch level.
If you have, for example, an instrumented Java application that calls ElasticSearch - you can see request count, failure rate, response time for OPAQUE service (not instrumented). Dynatrace can see when the code of your application executes a call to another service and when it came back.
You can see how it look in Dynatrace - with fully instrumented ElasticSearch on screenshots.
In my case, I call elastic with curl. So I can see this call and PurePath because ElasticSearch is instrumented - agent in Full-stack mode. I can see exception and e.t.c.
I wouldn't be able to see these CURL PurePaths without instrumentation.
In infra only mode you can additionally setup extension to get ElasticSerach metrics:
JVM metrics tab will not be avaliable in infra only mode.
I hope this helps, have a good day!