System.Text.Json.JsonException: The JSON value could not be converted

Your input json has an array as the base token, whereas you're expecting an object. You need to change your deserialization to an array of objects.

var elevadoresModels = JsonSerializer.Deserialize<List<ElevadorModel>>(jsonString);
elevadoresModel = elavoresModels.First();

Your input JSON is an array of models, however you're trying to deserialize it to a single model.

var models = JsonSerializer.Deserialize<List<ElevadorModel>>(jsonString);