Thank you, very interesting.

Yes, regarding puzzle #66. So, what would be the safest way to spend the coins to another wallet then?

I mean, what is even the point of spending time & resources on finding the privkey if it is then impossible to spend the coins (or at least most of them) to another wallet safely because an army of monitoring agents will attempt to steal the coins by cracking the privkey using kangoroo with the newly avail. pubkey.