Donald Trump is a loser. Several of his handpicked stooges he endorsed have lost their races and this is just another one. This loser lost the election in a blowout and his sycophants think he will run in 2024 when he is even less popular in the GOP. 
Trump's big Texas loss sent 'shockwaves through the former president's inner circle': report

Since the November 2000 election, Trump backed candidates have not done too well. I think this is something the Republican leadership is ignoring, hoping this is all just a fluke, but I think it reflects the new reality. In any case, they have gone too far to turn back now.
Losing the two elections for the U. S. Senate in January, 2021, Losing other elections. A recent election that bucks the trend was Mike Carey winning a primary in Ohio. But that may have more to do with Trump funneling in a massive amount of cash more than Carey receiving Trump’s endorsement.
I think it is likely that by November of 2022, the new reality will become undeniable. Trump has his fervent supporters, can still raise a huge amount of cash, but whose endorsement will hurt a candidate in a general election. Trump has lost the ‘Rhinos’, whom he has disparaged but always needed to win. I am looking forward to that month.