Aw man, that's tough but you are right, the radios are important since you actually make calls. That's a bummer considering the journey you have been on to get to the G7+. Even so, it could become really annoying, it's up to you of course.
It's not the same thing, but I got to a point a year and some ago when I had to switch carriers because of the random zones with issues no matter the phone when at work.
VoLTE is important. It's kind of easy to not care about that if the places you go and frequent are just great with reception in general, but as you experienced, the difference can be night and day. I wish you good luck with your decision.