I hear you! Trying to keep everyone on the same page is like herding cats; nigh on impossible lol.
Do you have other pets? I ask bc if you maybe had a more solid relationship with a small animal vet they might be able to personally recommend a large animal vet. Or maybe a horse friend / previous trainer that could recommend a vet / farrier? I’m not saying that your current vet isn’t lovely, but rather IMO it’s crucial to have at least one actor in the soap opera that you trust implicitly. And I can see how it might be hard to have that level of trust with providers that are new to you; particularly if your pony has been having issues!
My vet is human and thus I expect him to make mistakes (in 20 yrs he’s made one), but I trust him completely to be straight with me, do his best and to have my animals’ best interests at heart.