Thank you for the suggestion, but I described my own approach to solving it. I know it will probably take longer.
If I’m not mistaken, in your example you solved a private key with missing characters in raw HEX format, while mine is in WIF format, and the process is a bit different there. I’m also not sure that the same method can be applied in my case.
That small puzzle was actually very useful for me because it showed that this particular method probably won’t work for my situation.
So I will continue with my slower and more methodical approach: I will substitute the first 3 unknown characters one by one, and for the remaining unknown section I will simply define a range and check it.
I adjusted my solver to work with broken WIF's - different to the method used for Puzzle6. Puzzle6 made me realise it's possible to solve (with some complexity shift) on WIFs with gaps.
That is why I suggested you create a new WIF key on
https://iancoleman.io/bip39/ or wherever, post the WIF with the broken parts only (same structure as yours: [26 known characters] + [3 unknown characters] + [5 known characters] + [10 unknown characters] + [8 known characters]) and the pubkey and I'll return you the full WIF.
If you are not interested, no worries and good luck!