Amen to this. I've followed pretty much the exact same path as you (pfSense instead of OPN though) and reached the exact same conclusion.
I have a sizeable networking background, but still absolutely hated having to keep up with this many moving parts. I very much didn't enjoy troubleshooting this setup.
Plex' Android TV app (ATV) is a travesty in regards to pretty much every feature that matters.
From broken playback state tracking, "currently watching" that just won't go away (obvious local state management issues), subtitles that randomly won't show up (no matter what you do), un-configurable +30s/-10s skip options, outright crashes (that toss the local state of whatever you were doing), fun with HDR playback (good luck, 0 handholding. You just have to make all the stars align yourself) and many, many more problems are routine.
Despite all this though, it is (or at least was 9~ months ago, when I made the switch) so much better than Emby (and sorta, by extension, Jellyfin -- which was much worse) on the same platform that it's astounding.
I remember being super impressed that metadata matching was mostly working for a predominantly ASPAC focused library. Library management in general is much better, now that I think about it.