I assure you the signal path for the Lumin playback is correct. It looks different from 1.4 because 1.5 expects a more detailed reporting from RAAT endpoint if it is a MQA decoder or renderer. Lumin has already implemented it 3 months ago. As for the other non-Lumin setups, they may have other technical limitations or need further enhancements to show the same thing.
Please do not worry about the processing speed indicator. Your signal path shows that Roon Core is doing passthrough and not performing any processing.
That being said, it’d be worthwhile to try shifting the MQA Core decoding from Lumin to Roon Core by setting MQA Capability to Renderer Only. See if you hear any difference in SQ. Reference: Roon Decoding MQA Listening Impressions