Re the shoes/socks combo-This is critical.
I remain convinced that one of the best things COSCTO has ever sold are their 4pk/6pk 80% Made in the USA Merino wool "hiking" socks (Kirkland). Less than 5.00 per pair. Simply dynamite stuff and a near exclusive sock used on our Philmont trek. No blisters or hotspots by anybody using them. They can pile a bit if you do not wash them inside out.
https://www.ebay.com/itm/37344195285...kAAOSw-iFgEeJz
Re rucking and shoes and athletic shoes in particular. They are a consumable. Treat them as such and move on. If you like a shoe/boot model, buy two and alternate pairs and wears to extend life. 300 miles shoe life when rucking 50+ lbs does not strike me unreasonable at all when I have heard that 500 miles is the max on a pair of running shoes. You got one set of feet, never cheap out on shoes and socks when it counts.