A cheaper alternative might be to slip an expired credit card under the insole of your current shoes, right above where the inner metal cleat retainer is located.
Your hotspot is likely to be a Morton's neuroma or hotfoot, and I suspect it is because your metatarsal bones are being squashed together and pinching the main nerve trunk through your foot, producing the hotspot sensation. This is caused by the insole compressing into the depression where the cleat retain is located. Putting a credit card in there builds the surface back up.
You might also slip in a new pair of insoles.
Try it and see if it works. It might save you a few hundred bucks. If you ride on rural roads, and you aren't a performance cyclist seeking to eke out a few seconds a mile, I don't think carbon-soles shoes are going to be worth the expense for you.
I ride randonnees and other shorter rides, while I have a pair of carbon-soled road shoes, I would never consider using them in those circumstances.