2/12/2024 SOLUTION

So it was the neutral safety!!! I’d come to my wits end, wasn’t able to test continuity at home so gave in and brought it to the stealership. They ran through everything I’d done and all the new parts and determined the neutral safety switch wasn’t engaging.

From Toyota “Verified starter relay is not clicking, checked power at relay and had abnormal voltage reading at pin 1. Traced back to neutral/park safety switch and found a poor connection. Reinstalled neutral/park safety switched and verified starter relay now has power. Vehicle now starts after getting to normal operating temp”

Now it starts like a charm every time. Not sure if it was an external attachment or internal component (the tech left for the day when I picked it up) but it’s resolved. I disconnected, cleaned, and reconnected the plug 2x over the past month and a half so to no avail so I assume it wasn’t seated fully and would be out of spec when the engine/trans got to temp. Glad this is sorted and not some electrical gremlin.