Replacement components for fried Teeny 4.0s

Hi all. I have a small (5 boards) but ever growing collection of Teensy 4.0s that I have destroyed, almost certainly all of them are from over voltage on digital inputs.

Today I took a look at them to see if I could figure out what was wrong, but there's nothing obviously damaged. Perhaps the LDO (U4) and external flash (U2) look like they might show signs of damage but can't be certain.

My question is: is there any precedent for repairing boards or should I toss the collection? Happy to buy any parts that might be common culprits and hot air on replacements myself (assuming the actual micro and the external flash are not an option for re-programming reasons).

Mostly asking as I feel guilty throwing away nice fast parts during a chip shortage...

Thanks for the great product!
The main processor is most likely destroyed. It's the part which takes the damage when I/O pins are overdriven.

If you have access to special BGA rework equipment, and if you're able to get the main chip (currently out of stock pretty much everywhere), repair might be possible. But the small quantity price on these chips is almost as much as just buying a brand new Teensy 4.0, so probably not worthwhile to attempt repair if you're buying just a few chips from a place like Digikey.
Thanks for the fast reply! Sounds about right... I will most likely just scrap them.

One more thing I should have mentioned is that I can here an audible frequency from the USB hub powering a few of the broken ones (as though it is over currenting). Does that sound it could be a problem at the LDO? And if so would the assumption be that the micro is also done for or might it be worth trying to swap just the LDO?