Mongodb Bson type to Json

Here's the solution:

On the client side

        // serializer
        var serializerRegistry = BsonSerializer.SerializerRegistry;
        var documentSerializer = serializerRegistry.GetSerializer<T>();

        // filter and update
        var filter = Builders<T>.Filter.Eq(e => e.Level, 2);
        var updates = Builders<T>.Update
                     .Set(e => e.Name, "foo2")
                     .Set(e => e.Path, "foo2 path")
                     .Inc(e => e.Level, 1);

        // get the string of the filter and the update
        var filterString = filter.Render(documentSerializer, serializerRegistry);
        var updateString = updates.Render(documentSerializer, serializerRegistry);

        // instantiate patch object with properties to json
        Patch patch = new Patch()
        {
            Query = filterString.ToJson(),
            Update = updateString.ToJson()
        };

        // patch object to json
        var patchJson = patch.ToJson();

On the server side

    [HttpPatch]
    public async Task<IActionResult> PatchOne([FromBody]Patch patch)
    {
        // don't need to ModelState.isValid, it's done on binding
        
        try
        {
            var update = BsonDocument.Parse(patch.Update);
            var filter = BsonDocument.Parse(patch.Query);

            var result = await _serviceBase.UpdateOneAsync(filter, update);
            
            ...

        }
        catch (System.Exception ex)
        {

            return StatusCode(StatusCodes.Status500InternalServerError, ex.Message.ToJson());
        }
    }

Global Modals (my solution structure)

public class Patch
{
    [Required]
    public string Query { get; set; }
    [Required]
    public string Update { get; set; }
}

Thanks for your help !!