QN55 is not a complete model number so I can’t be sure what you have. But at a high level, Samsung definitively differentiates control features across their lines and model years. Not providing explicit input selection certainly was one such thing observed in past years. For many model years, most models of Samsung do now support direct input selection via IP control.
As an aside, we do also support control of Samsung TVs via our Smartthings integration. You can therefore possibly use the same technique that worked for you from within Roomie. There are numerous ways to control Samsung TVs depending on the year/model/etc. Serial is a very good one if your model supports it.
Depending on the full model, one thing we often see is feature stripping at the low end of the market. Samsung commonly strips useful control features from units sold at CostCo for instance.