Scaling on the FLX1 is pretty good at solving those issues but due to the way developers can make apps its not something always in our control. Personally, I dont have any issues in my daily usage.

There's the mobile tweak tool you can get that allows you to forcibly scale a app that doesn't fit right to make it fit better. Not sure if it's in the repositories or I'd you'd have to manually install it.

Most apps will scale - thanks to linux mobile succes in various platforms.

Which does not scale ottb (like nextcloud) you can use phosh-mobile-settings app to scale-to-fit function.
There are still some apps which needs this but most actively maintained linux apps are allready scaled properly.

There is excellent scaling for example in these apps (in furios)
File browser (portfolio installed by default)
Internet browser (firefox - better than ever - installed by default)
Music player (g4music - installed by default - also lollypop works)
Video player (celluloid - installed by default - also livi works)
Sms/mms app (chatty - installed by default)
Phone app (gnome-calls - installed by default)
Matrix app (with Fractall or cinny everything works - Nheko works also when someone sorts out some qt6 issues)
Telegram-desktop (you need to scale telegram little bit smaller from Telegram advanced settings but after that perfect)
pdf viewer (evince)
Software center (gnome-software)
calculator (gnome-calculator)
calendar app (gnome-calendar)
contacts app (gnome-contacts)

And these are just to name a few :).
I think one of the last scale issue is how to force every app to use adaptive file chooser. I believe it will be solved but it is surprisingly complicated because you need to fix it per app in many cases. (Most apps are all ready using the adaptive file chooser)