With hindsight, it looks like a number of factors (including what you have identified) conspired to cause Arsenal’s implosion, but it wasn’t inevitable - and I wouldn’t have had any complaints if we’d amassed over 90 points and been pipped to the title, as they would have deserved it.
What was never in doubt however, for me at least, is that we would go on a run and seriously challenge Arsenal, which would bring its own pressure to bear upon them. I found people using the first half of the season as a counterpoint to this view in the early part of this calendar year to be bizarre, as if no lesson has been garnered from the run-in to the last few seasons, 2020/21 apart, when we took our foot off the gas after securing the title.
Even in 2017/18, after the title was won, we kept going relentlessly (Huddersfield home apart) as history beckoned.
Pep has a magical way of getting the job done in extremis, including the foregoing 2020/21 season when we looked toast in early December and went on a 21 game winning run. Obviously there’s the 14 games at the end of the 2018/19 campaign, and last season too. All incredible feats of team sport.
Tactically, Pep is incredible, as is the way he improves players, but his motivational skills are as much as asset. He knows what to do to deliver the goods in the league better than any manager in English football history, as the foregoing title wins, individually and collectively suitably demonstrate.