Thanks. That was a big help. I decreased jerk from initial setting of 8mm/s to 3mm/s in 1mm/s increments and found 4mm/s to be the sweet spot. I went from a .30mm middle width with 30.27mm total width at the corners. Now I get 30.16mm corner measurements. Any slower settings have no effect other than making the perfect 30mm middle measurement smaller. Print speed is 50mm/s. I also lowered X and Y acceleration in firmware from 1000mm/s to 500mm/s to match all the other 500mm/s settings.
This leads me to believe I've maximized jerk/acceleration but still have another small tweak needed to get spot on. Those little bumps aren't a big deal but I view it as an important learning process to gain a better understanding of all those settings in Cura. It's a good thing I'm retired and have a lot of filament on hand. LOL. In watching this CHEP YT video it appears this is mostly a Cura 5.0 beta issue. Until there are further updates to the beta I can just clean off those bumps for now and move on to other tweaks.