I think your best bet would be to setup a Bulgarian company and register the car there. You might be limited in choices in the Bulgarian car market but you can always buy the car in Germany on export plates and drive it to Bulgaria.I don't think either of us will convince the other. I'll admit I am in the minority because I would rather drive half a day on back roads and travel quarter of the distance, rather than a full day on a motorway. My older 911 Carrera has all the sound deadening and carpets removed and the other 911 GT3 comes from the factory with reduced sound deadening. Both have quite hard suspension and low ride height. That's why I don't drive full days. You are right, it's just too tough.
Plus, very difficult to find manual transmission cars these days. New 911s are too big and don't interest me.
The solution I personally did was setup a foundation in the Netherlands, not sure how it works with insurance for foreigners but since I am Dutch myself that wasn't an issue. You can setup the Foundation online and will cost anywhere between 500-1000 euros, also plenty of storage option in the Netherlands and a professional car market.