I monitor the output data format of my Vizio sound bar with a Vizio Smart cast Mobil controller. This is done wirelessly, and gives a reliable indication of the actual data format of the audio signal. I have a Roku Ultra streamer connected to a Vizio TV. I have been used to seeing a Dolby Digital + indication and figures this was the best for accurate sound. I was surprised when watching a HBO + show to see the controller indicate a LPCM format.
I assumed this was an inferior data rate until my research showed it was possibility better. And the sound was awesome.
So yes, under these conditions, and with this lineup of equiptment, my Roku streamer will recognize and process a LPCM signal.