Best Streaming and Sound Setup for Bravia 8?

I'm excited to be getting my first OLED TV next week! (Bravia 8, K55XR80) It replaces a 20-year-old, 50" 720p Panasonic Plasma which has a fantastic picture--but not quite as fantastic as the Sony!

Current setup:

• Roku Express 4k+ feeds signal to Onkyo TX-NR509 (2012, with 1.x HDMI input/output)
• Onkyo processes audio and passes to my 5.1 speaker array
• Onkyo passes video via HDMI out to the Panasonic, which acts purely as a monitor

New setup: Question

• Keep the same configuration, and let all of the Bravia 8's streaming and audio marvels sit unused?
• OR, ditch the Roku and use the Sony's Google TV streaming platform, and pass audio to the Onkyo via digital audio output?

I(Note: I don't have any hate for the Roku, nor am I married to it. It only hiccups and needs a reboot very occasionally. The interface is fine with me, I only use about a half dozen apps.)

Ideas/tips appreciated!