My guess would be the starter. You mentioned that the battery was showing good voltage at draw according to your tests and the battery distributor's testing.
These starters are prone to overwork failure especially because of the start/stop feature which I think is a ploy for stealership repair.
After a while, these starter motors will generate metallic dust through excessive use which can cause a myriad of starting problems, including a total short out. The dust spreads onto the armature and starts to compromise the winds. I also have a 2020 and had to replace mine a few months ago because the starter flat shorted out. In my case, it kept blowing the starter fuse but in yours, if it is partially shorted, it can cause a big amp draw which seems to be the problem in your case. Even with the help of your starting block, it was unsuccessful.
With that said, that would be my next point of focus. Either way, good luck!