In the last week I have dove back into this finally with this new year and a new attitude. It seems like this last Saturday I got a little bit of a win. I still have one or two electrical gremlins. But in the 650xi's config, in the Com Settings, I changed the RX Squelch Setting to "Advanced". This opened up not just 3 but actually 6 settings, a Low, Med, and High for the radio bandwidth. ALSO, I just noticed for which I think might have been some of the issue, that there was also the "Carrier" squelch settings if you scrolled down in that new advanced menu! I did not see those until this trouble shoot time. Meaning those 3 Carrier settings likewise as the RX Squelch. Prior to now, I had changed the RX up to 95%. The Carrier was still at the garmin default of 57%. I dropped all 3 settings of both groups down to 5 %. In the last two days of test flying, settling frequencies one-to-one on each Com, the result now seems to be now that I have the same RX range, as well as the TX ranges. Also, today I called a Center that was 100nm away, result was both the GTR200 and the GTN650xi received seemingly equally good, and clarity report back was 5/5 clarity.
Honestly I have changed so damn much; Rx squelch setting up n down, and changed out a couple wires, and fixed a ground that I yanked out fumbling with this crap, plus there is more, and again so many config settings changes, that I don't know what is the smoking gun here. I suspect this recent change that worked is either the Carrier Squelch, OR the RX Squelch.... because I changed all these down and to be the same prior to the last two recent flights....I just don't know which was the fix. But one or both of those did some sort of improvement.
Still doing more testing, but right now I am at least CONSIDERING going back to using the gtn 650xi, and its Com as my primary Com1. Verdict is still out. Still fighting another gremlin, 4 weeks ago was flying an ILS and my audio panel went nuts and shut off. At home I checked all wiring, and found nothing. This has not reoccured. I roll my eyes in frustration, but I guess we will see how this plays out.
Summary, what I can figure out is now, at least it seems, that the 650xi's Com settings need to be in Advanced, and ALL 6 settings need to be set all at 5 %.