I saw that too on my one African hunt. Different PHs all had different boots. My PH was a young guy and wore 6" zip up boots and shorts. No gaiters. Functional. That's probably what he could afford as the same for MOST of us. I wore a pair of Vasque hiking boots that I already had with 5-11 cotton pants. I had sprayed everything with Permethrin prior to the hunt but my PH had never heard of it.You just went down a rabbit hole. People lose a lot of sleep over this subject around here for some reason.
I've had four Ph's and they wore four different boots. First was some heavy soled hiking boots, no gaiters. second, old school chukka type boots with leather gaiters, third slip on ankle high hunting boots I noticed a lot in South Africa and third some lace up boots. I don't recall what type of gaiters on either of the last two. I have a pair of Russel Thula Thula PHs and some Texas Hunt Co gaiters. Love both of them, though others do not and the Texas Hunt Co products are no more. Courtney boots are pretty classic and have their fans, Boyt Harness makes some good canvas gaiters I'd go with before I'd go with leather.