How do I retrieve all appointments for a specific date for a specific user, and only those associated with an AbEntry?

I am trying to retrieve all the appointments that excludes any that:

do not include an AbEntry,
are on a specific date,
include a specific user.

I have been able to use this to get everything on a specific date:

"StartDate": {
	"$RANGE": [ 
		"2026-03-04",
		"2026-03-04"
	]
}

But I have been unable to figure out how to return only results that include a specific user, or that only include AbEntries (any AbEntry). I know I can filter after I get all the appointments into my app but I would prefer to do it somehow in the request itself.