Not ECDLP but DLP so Pollard Rho and Pollard Kangaroo should be applicable no?

Doubt. The creator of this puzzle is a very early adopter (if not even satoshi) and he probably has many, many more BTC than this puzzle is worth right now.

Oh man. Don't waste your time. There is a whole paper about trying to crack wallets by using the lattice attack. They tried most transactions already... . Try something new.
If you want to try anyways: best way is to modify bitcoin core  so it saves all transactions r,s,z to a file. I have those modifications but won't give them away for free.

PureBasic executables get false positives cause some ransomware used PureBasic. You can search it with google.

Hi,
your upper range in searchspace is around 116 bit.

As you don't know in which bitrange the key is exactly to be found it will increase the searchtime.
I don't have the math but I think when using pollard kangaroo and you don't know the exact bitrange (somewhere between 1-116 bit), you will increase searchtime to the same (if not even more) as a regular 120bit key. BSGS will need too much memory and prepocessing time.

You might expose your calculations for the target key so people can audit and you could get more feedback.