Whether or not UCF won the natty and regardless of the final score of the TCU Georgia game, those programs did compete at the highest level. And they competed at that level more recently (and in TCU’s case, more consistently) than UM has in a long time.
By your rationale, we should be relegated down to the lower division.
2022 TCU wouldn't even qualify in your argument because they won a power 5 conference.
As for your second point, If Miami was consistently at the bottom of the ACC standings they probably should be relegated to the lower tier. But they haven't been at the bottom of the ACC. They've only had a losing conference record in 5 of their 18 seasons.
The facts are, despite occasional G5 teams having nice runs, their overall record vs p5 conferences is terrible.
The AAC which is probably the top G5 conference, has a .319 win percentage vs P5
Conference USA- .181
MAC-.158
Mountain West-.291
Sun Belt - .276
That's an all time win % of .217
But wait, isn't the gap shrinking? aren't G5 teams generally better now than years ago?
Over the last 20 years, their win percentage vs the P5 is.189
over the last 10 - .182
over the last 5 - .168
The gap is only getting bigger and it's pretty much due to the fact that even middle of the road P5 programs have WAY more money to spend on athletics than even the most successful G5 teams.
There's a handful of G5 teams that you could make an argument to join the big leagues but they rarely have long periods of sustained success. And even then it's just success against other G5 programs.