Hey. This is an endeavor that has been years in the making. :P
If you want the top quality picture and sound... The HTPC is the best solution. Consoles don't even compare, I'm not even kidding.
I'm not sure I follow you. What does a noisy electronic environment have to do with digital audio. Either the ps4 decodes it to 7.1 and sends it in pcm format to my amp, or it just sends the bitstream and lets my amp decode it for zero difference. 5.1 pcm 192/24 worked flawless already on ps3 with Akira.
As for deinterlacing, I think I have 2 blu-rays that have interlaced video out of 500. It's very rare. I also like the movie the way it was meant to be seen without enhancements, no artificial noise reduction or, gasp, detail enhancement, judder free 24fps is what I want which blu-ray kindly delivers. I turn all that shit off on a new tv as soon as I set it up. I've had the pro run a blu-ray upscaled to 4K and the base ps4 run a blu-ray with the tv handling the upscale. I see no difference, both look amazing.
All I need the player to do is to decompress the video file and send it over, don't alter it. The tv does all the enhancements, however I have it set up that when it detects a 24p signal it switches to a setting that leaves the picture the way it is. Smooth motion, reality creation, noise reduction, motion flow, cinema pro, the fuck! It can enhance the contrast with local dimming and smooth gradients to 10 bit to hide 8 bit color banding, that's it.
You're happy with HTPC solution and that works for you. It probably looks great on monitors that aren't made for movie viewing (and tv as well ofcourse). I've selected my displays based on how well they can show the original signal, warts and all.
I guess I don't want the best quality, I want the original quality :)