I don't baby mine, but I've never spun a tire on acceleration.
Yotota is correct; using the rear locker around town is a poor idea. There's a reason differentials are there.
Well... here's the Fumoto plug I installed, so it has the thread size.
https://www.amazon.com/dp/B01HP5UZIO?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_2
Mess? Good grief. There's zero waste there. I've never seen a clean removal of the tenderloins with the gutless method. And of course, there are the liver and heart that are usually left with that method.
Here's half of that mess that's nearly skinned. Clean as a whistle.
Here's a pile of...
So the problem could be either on the Toyota side, or the iPhone.
I've never had this issue in 18,000 miles and have the same software (and probably the same hardware) as your truck. I've got an iPhone 15 with IOS 26. Is your phone old? Is the IOS up to date?