I have the same problem with buying shoes online which is made far worse by the fact that for non-US people you generally have to swallow shipping and tax costs even when you return items. However now I know that Crockett & Jones UK10 in last 341 is a perfect fit for me so I am now trying to use that as a base.I'm in Catania, Sicily, where the only shoe options are the low-cost plastic high street shoes: Aldo, Bata, Geox, Nike, etc.
When life returns to normal I guess I need to fly to Florence/Rome/Milan for an intensive 2-3 days shoe shopping.
You can also still go and get your feet measured in those shoe shops you are talking about.