My B4A-IDE looses the connection after 30s`, if the B4A Bridge runs in Background (Huawei P30 Pro). As soon as i open the bridge from the notifications bar, its connected again.
Works in my older Samsung S8 without problems.
I disabled any energy saving options and rebooted phone and pc several times, without success.
I have the exact same problem with my Huawei Y6 2019. Tha power saving features on spare Huawei phone is just reficulous. When I turn the screen of it kills B4A-Bride, it kills widgets alot sooner then them my other devices, and most of them don't like my widgets and B4A-Bride. I know that device manufacturers want to try to find ways to save on battery power, but Huawei really are going to far. Also Huawei devices also warned users of an apps using what they think is too much battery power, they pop up a bright red warning in the notification area at the top of the screen...
under dev options there is the setting to keep the screen on when usb is connected which prevents that the screen goes off and power saving options kick in.
never had a problem with my Huawei but I don't use the bridge just the straight connection.