If the mash/fermentation is done well, the main driver for final pH is the yeast strain. Dry hopping raises pH and higher pH’s sharpen bitterness (+4.5). Each strain has a “sweet spot” for finish pH.
I don’t always measure it, but I do time to time. Higher wort pitch pH can effect pH, but it has to be way out of line, 5.4-5.5 at pitch or higher.
A careful study of historical peer reviewed brewing industry dissertations (via sources such as the 'Wiley Online Library') reveals that for many decades now (nigh-on approaching the century mark) it has been settled that a room temperature measured pH of 5.2 achieved during the boil is the ideal pH at which to pitch yeast. And the same undertaking reveals that a mash temperature measured
5.4 pH (roughly 5.55 to 5.6 pH if measured at room temperature) is the ideal mash pH that was settled upon decades ago. This requires two pH adjustments. One best made pre-mash, and one made either pre boil or (perhaps best) during the active boil. The best hot and cold break, and the least 'quantitative' requirement for fining addition occurs at 5.2 pH as measured at room temperature.
IMHO, the 1980's evolution of home brewing, and of the multitude of nigh-on worshiped non peer reviewed authors who support it, plus much of the micro-brewing industry that evolved directly from this homebrewing base, got the previous industrial level established and documented ideal 5.4 mash pH target wrong at the very onset simply by incorrectly presuming 5.4 to be a room temperature measured
pH target. And the same generally tend to ignore the secondary 5.2 pH target criteria.