Going to strip them back, use 'leather filler' on the cracks and dye.
I think you could achieve a really good result. The leather is quite thick. Nothing bad will happen if you remove the top layer with wet and dry paper. Start with 100 grit and finish with 1200. Then put on a new finish with a pigmented layer (dye or paint) and a lacquer e.g. https://fiebing.com/product/resolene/ or https://www.angeluspaint.co.uk/c-9-finishers.aspx . Fiebings and Angelus have about a billion choices for you.
The hard part will be getting the filler to stick and making it look like leather! I'm looking forward to seeing your result! Here's some inspiration https://www.furnitureclinic.co.uk/leather-repair-kit I can't find an example with deep cracks on shoes. You might be the first to attempt it.
Ah yeah, I wasn't sure about the finisher, haven't bought any yet. Is that strictly necessary if the boots were a satin/matt finish to start with and that's what I'm trying to achieve?
I think you could achieve a really good result. The leather is quite thick. Nothing bad will happen if you remove the top layer with wet and dry paper. Start with 100 grit and finish with 1200. Then put on a new finish with a pigmented layer (dye or paint) and a lacquer e.g. https://fiebing.com/product/resolene/ or https://www.angeluspaint.co.uk/c-9-finishers.aspx . Fiebings and Angelus have about a billion choices for you.
The hard part will be getting the filler to stick and making it look like leather! I'm looking forward to seeing your result! Here's some inspiration https://www.furnitureclinic.co.uk/leather-repair-kit I can't find an example with deep cracks on shoes. You might be the first to attempt it.