To my surprise the battle between Goliath US based Wendy's and David Dutch street food restaurant Wendy's isnt widely known in the war.app community.
So here, for your enjoyment the basics of the case.

Wendy's corp wanted to expand to the Netherlands but found out that the name "Wendy's" belonged to a small restaurant in a small Dutch town.
20 years(!) of legal battles followed as the Americans are used to a legal system that in the end always the party with the largest bank account.
Thats not how Europe works, so justice prevailed and the small business exists to this day.
And Wendy"s ? Never made the leap over the ocean to the rich kid of Europe, The Netherlands.

With translate you should be able to read the full story on these 2 sites:
https://inaday.eu/blog/wendy-snack-strijd-merkregistratie
https://www.nu.nl/economie/6165583/zeeuwse-snackbar-wendys-wint-rechtszaak-van-amerikaanse-keten-over-naam.html?referrer=https%3A%2F%2Fwww.bing.com%2F

The instagram of European brand Wendy's
https://www.instagram.com/wendys/

In the US, too, you are allowed to keep a name if you are using it first and in good faith. You've misunderstood the lawsuit. It was Warlight/Warzone/War.app claiming Activision shouldn't be allowed to use the dictionary word "warzone" in their game names, not the other way around.

Those Wendy's-type trademark unicorn restaurants are all over the US too:

https://en.wikipedia.org/wiki/Burger_King_(Mattoon,_Illinois)

https://thesubwaypizza.com/

In fact, it's the EU system that worked worse for Warzone. In the EU, Activision just filed for and got the EU Trademark for "Warzone" first, because the EU is first-to-file, not first-to-use. They've had it this entire time. It's only in the US where Warzone had the ability to block the trademark because they used it first.