react-router doesn’t do mobile app routing. The newer versions of react-router (6, 7) are moving toward SSR, and all of those new features are basically useless for a mobile app (the app is rendered client side). So if you switched to a “new” version of react-router, you will lose the ability to do things like tabbed mobile routing and gain the ability to do SSR, which you won’t use in your mobile app anyway.
react-router doesn’t have an EOL, so v5 is still supported (basically limited to security fixes at this point, but it is not abandoned).