A lot of vehicle rental has been pushed out to "neighborhood dealers". Small businesses like gas stations and car lots store U-Haul equipment on the property and rent it out. Highly convenient in theory but in practice is often frustrating with odd hours and unenthusiastic owners.
It is interesting to see what people value. Never heard of a 200 mile test drive (singular).
For 45k give me one of these and keep the rest. https://bringatrailer.com/listing/2001-mazda-mx-5-miata-special-edition-29/
I'd change it for sure, drop the pan and see what it looks like, clean the magnet etc. Fill with fluid and drain/suck it out again after a hundred miles to get what was left in the TC.
Probably water sitting on the bottom, very common. Pull the bowl off and see what you find. If the main jet is incorporated into the bowl nut, that may be clogged also.
In my experience debris from the tank is held back by the micro screen filter and never reaches the carb. It's water reacting...