Dynamic Brush Size Keystroke (control+option+drag) Not Working in Photoshop CC 2019

I'm running Photoshop CC 2019 on a Mac OS Mojave: version 10.14.5

I have recently updated my machine to a new version, and as is the tradition with Mac updates, something in Photoshop has gone haywire. Now the control+option+left/right drag no longer allows me to change my brush size on the canvas. The keystroke does work when I hold control+option and then drag to either side with my Macbook's trackpad, but either the machine or Photoshop refuses to do the same action for my stylus.

I've already tried to fix the Photoshop shortcut preferences by resetting them and manually inputting the keystrokes I want; Photoshop's shortcut panel no longer seems to accept "control+option+drag" as a keystroke command at all, despite me having used it for years in the past. Brush size adjustment shortcuts is currently set to the "[" brackets option, which is wildly useless since I am right handed and my stylus has got to leave the canvas for me to get to those keys.

I've attempted resetting my Mac's keyboard and tablet settings as well, to no results.

This was an immensely useful shortcut for me as I am a professional artist, and the work just goes faster if I don't have to open the brush presets panel, or take my stylus off the tablet every time I need to adjust brush size.