$apply is not showing meta data info when I use IActionResult

I have Get action in controller:

        public IActionResult Get(ODataQueryOptions<TEntity> queryOptions, CancellationToken cancellationToken)
        {
            var query = MyDBContext.Set<Student>().ToList();
            return Ok(query);
        }

When I send this query: Student?$apply=aggregate($count as OrderCount)
It is returning value without meta data.

Actual:

[
    {
        "OrderCount": 3
    }
]

Expected:

{
    "@odata.context": "https://localhost:44383/$metadata#Student(OrderCount)",
    "value": [
        {
            "@odata.id": null,
            "OrderCount": 3
        }
    ]
}

It is working fine when Get looks like:

        public IEnumerable<TEntity> Get(ODataQueryOptions queryOptions, CancellationToken cancellationToken)
        {
            return MyDBContext.Set<TEntity>().ToList();
        }

It is causing problems when entity is Open Type. In open type it looks like:

{
    "$type": "System.Linq.EnumerableQuery`1[[Microsoft.AspNet.OData.Query.Expressions.NoGroupByAggregationWrapper, Microsoft.AspNetCore.OData]], System.Linq.Queryable",
    "$values": [
        {
            "$id": "1",
            "$type": "System.Collections.Generic.Dictionary`2[[System.String, System.Private.CoreLib],[System.Object, System.Private.CoreLib]], System.Private.CoreLib",
            "OrderCount": 3
        }
    ]
}

My project is in .NET 5

Start with the controller Get action using IActionResult and ODataQueryOptions and compare it with the IEnumerable action that works. Reproduce the Student?$apply=aggregate($count as OrderCount) request, including an open-type entity, and trace how the result is serialized. Done means the response includes the OData context and value metadata rather than a raw array or EnumerableQuery wrapper.