You’ll see the 2015 version of Trump when he’s a challenger again (in 2024).
Trump was the frontrunner in 2015-2016 primary too. Furthermore, he only skipped one debate, right before Iowa, which arguably contributed to him losing that state to Ted Cruz.
Nobody likes cowards, and Trump saying he fears being “libeled and abused” in a GOP primary debate here in 2023, i.e., - the other candidates will say mean words about him - is laughable.