I use leather dye and not shoe polish.
If you have blemishes or cracking (not rips) the dye will even out the blemishes and get down into the cracks and color the underlying backing.
Then use a good leather cleaner and let dry for about 30 minutes.
Looks new.
If you search Isuzu Leather Dye you'll get some hits. For the black I just use the Kiwi product from Walmart. For the grey, use a product from the net.