OK Angelo,
(I'm Italian, too, but) I'll continue in English, so to allow also other colleagues to help you.
If you search a bit in the community you'll find a lot of topics related to the BT comm's toward Arduino (are you using a HC05/6 or an ESP32 ?).
In few words, to receive from Arduino on a BT line, you need a clock that shall poll the incoming BT line with a frequency, at least, double of the transmission one (i.e. if your Arduino sends every 100 ms, your app shall poll every 50 ms to be sure not to lose data).
Please also keep in mind that whenever you send a command from your app to Arduino, the response takes time to become available, therefore you cannot put in a sequence both the command sending and the response waiting. To receive anything you shall always use a clock.
So, typically, you shall set a clock that will fire (for example) every 10 milliseconds, supposing that your Arduino is not that fast, and whenever it receives a frame, it splits the contents and fills the label(s) accordingly. This is the theory, but for ready made examples you can have a look to @Juan_Antonio's web site (KIO4.COM) or the one of @ChrisWard (professorcad.co.uk).
You will also find a lot of other example by searching the forum tagging the words "bluetooth" or "arduino".
Or take a look to this post of mine, where you can find some help (I hope).
App not responding - #25 by uskiara
You'll find in that topic both an .ino and an .aia files together with a schematic diagram.
Best wishes for your project,
Ugo.