The anime community has, for as long as I've been a part of it (13 years or so), decided that anime is "animation made in Japan". This heuristic has actually worked pretty well.
But the lines are increasingly blurred.
- Japanese produced shows are outsourcing some animation to China and Korea, and sometimes taking direct funding and story writing input from the USA.
- Non-Japan produced shows are taking notes on what works, drawing on it for inspiration, and in rare recent cases even outsourcing animation directly to Japan.
- There is a TON of money in gacha games, and the biggest "anime" titles some people may recognize are gacha games, butand the majority of those are run 100% by Chinese companies. Ironically, sometimes sending them over to Japan for the TV adaptation.
Just like food: Italy may have "invented" pizza, but New York pizza is now its own thing.