on the most cheep smartwatches is WearOS a version less 3 installed. the OS
is closed and no any option to install an app. normaly such apps are compagnion-Apps.
They are two apps into a one (one for the phone and one for the watch).
this must installed on the Phone, where the Watch is connected with th phone. the
app will be installed on the watch. An app, created with B4A, can copy on a sdcard
on your watch, but cannot installed on your watch -> no chance.
i have tested it with the Wear Installer on the phone, but no luck.
the problem is, you can activate the adb-debugging (see the codes below)
on the watch, but you are not developper on the watch (for example 7 touches
on the wear os version) simultan at android.
here a few DZ09 codes : (this must be typed on the keyboard -> same procedure as you call a friend with typing a telephone number)
*#06# - imei
*#8375# - software version
*#00000000# - ZM entertainment or game center
*#1234# switches A2DP between PTS
*#993646633# – Launches service mode, which includes network settings, device, audio, and GPRS settings, etc.