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This will probably not take minutes unless you have a large GPU farm, but a few weeks is a more accurate estimate. Since Bitcrack can only talk to 1 GPU as far as I know.
Without an outgoing transaction, we don't have the public key, it will take longer.
Pollard's Kangaroo method also uses a start and end range. However, it does not support strides (AFAIK) because Pollard's Kangaroo algo is using it's own kind of stride while making the tame and wild kangaroos hop. There's no way to tell Kangaroo: "OK, there is a part of the private key at the end that's already known, don't search those bits". The consequence is that
for this particular situation, Kangaroo will take longer to find the PK (way too long actually).
Bitcrack, on the other hand, lets us specify an arbitrarily large stride and it converts it to a 256-bit int. Since in this case, 80% of the private key is already known, we can make the stride equal to that huge PK chunk at the end and effectively, only search keys between Kw11111111...... and Kwzzzzzzzzzz.......