Jack-HF2.21 doesn't exist. The last HF (Hongfire) version is v1.7.5. So either you've played the HF version indeed and it was v1.7.5 or you played v2.2.1 and it was ours. Based on how long you haven't played, you might have inherited habits that don't work anymore (fixed exploits, rebalance mechanics which make old advice or strategies not optimal, etc.).
However, there's a consensus that v2.2.3 is in the bullpark of difficulty as all other "good" versions (1.7.3, 1.7.5 and 2.2.1).
It is our will to respect the legacy of the game and respect the original intent of the dev', which was "challenging but still fair". This version especially was made with room for experiments and errors so it would be possible to survive the early game without needing a perfect run.
There is definitely room for improvement. You have many tools at your disposal to make training more efficient. With each playthrough, going back to the tutorial, and maybe reading some of the guides posted here, you'll see that you hadn't reached your full potential as a trainer.
Not a bug, it takes longer time for you to train your stats passively. You're not taking lessons yourself, but giving them, so you're not focused on improving, and therefore take longer time.
So if you look at it rationally, your stats as a trainer improve at a normal rate. You can even, if I'm not mistaken, go from 0 to hero in all stats in half a playthrough, and then enjoy the rest at max stats until becoming patrician. Perfectly doable even without spamming much.
Too bad, but don't discourage yourself. Many people didn't see the ending of Dark Souls in their first playthrough, but then they went back to it and it became a staple of "fun difficulty". Should be about the same for JONT.