Why was the film "Ford v Ferrari" renamed in most of Europe?

I can only somewhat speculate, since there seems to be very little documentation, but Ford is not known as a race car maker in Europe - people just wouldn't think of the Mustang (you can buy Mustangs in Europe, but they are only produced in the US). In fact, its image is that of a "boring", "workhorse" brand which makes compacts and family cars, although they are now moving towards SUV-style. A title of "Ford v Ferrari" would not evoke high profile, real world racing action - most people would expect a comedy about a complete mismatch.

https://en.wikipedia.org/wiki/Ford_of_Europe

According to director Mangold, prohibitions on using brand names in UK films forced them to change the title over here or in certain other European territories. In the US, the film still goes by Ford vs Ferrari.

https://www.radiotimes.com/movies/le-mans-66-movie-ford-v-ferrari-cinema-release-date-cast-plot-trailer-matt-damon-christian-bale/