Your Apple ID account has a country or region. That is probably the most important region setting, as it sets what Stores (apps, content) you can access, what payments methods are valid for you, etc. It can be changed if you must, but it drags a lot of other things with it. It is really meant for users that go live in a different country for a long time. Change your Apple ID country or region - Apple Support
Other region settings are about time, date notation, number notation, language, etc. You may set those as you please.
This hasn’t changed with iOS 17; it’s the same as for prior versions.
If you can, please give more details about what precise setting you tried to change, and where that setting is navigation-wise.