Coinkite (Coldcard) needs to offer a bounty to the hacker/hackers sweeping the funds

Coinkite needs to entice the hacker to become a white hat, by returning the funds in an organized way.

If they offered 10% -?% (after costs are deducted) of the value swept back I am pretty sure the hacker/hacker would prefer to avoid the headache of laundering stolen funds.

The process wouldn't be simple since you can no longer treat a signed message from a bad key as proof you own the key. You would need multiple pieces of evidence

This is realistically the only way users can get their funds back and it needs to happen quickly, before funds are laundered and more people start brute forcing the same key that were swept.

Its much easier to return funds to a hacked exchange, but coordinating returning funds users will be very time consuming, this is not something the hacker/hackers can do alone.

Returning the funds to the original address will just result in someone else sweeping the funds, to a new wallet.