Sixaxis Controller with Lubuntu issues

Question

I am trying to build a handheld/stationary retro console with support for PS3 controllers. The platform is an atomic pi with Intel Atom CPU which does a descent job on emulating up to PSP games.

Due to limited RAM which is further shared with GPU i want to stick with Lubuntu (lxde). So far i have tried 4 installations.

• Kubuntu 18.04 LTS
• Kubuntu 19.04
• Lubuntu 18.04 LTS (from lubuntu.me)
• Lubuntu 19.04 (from lubuntu.net)

I can't really go with 18.04 LTS versions though since they don't feature vulkan drivers and have other issues with the chipset (sound and hardware decoding). However if i connect my PS3 Controllers to KDE versions, i get a dialog asking to trust and connect the controller wirelessly (both kubuntu 18.04 & kubuntu 19.04). Lubuntu however doesn't print any notification about it.

If i check bluetoothctl and connect the PS3 controller via USB cable it says:

[NEW] Device 00:26:43:11:34:57 Sony PLAYSTATION(R)3 Controller
[DEL] Device 00:26:43:11:34:57 Sony PLAYSTATION(R)3 Controller
[NEW] Device 00:26:43:11:34:57 Sony PLAYSTATION(R)3 Controller
[DEL] Device 00:26:43:11:34:57 Sony PLAYSTATION(R)3 Controller

All installs had bluez and bluez-* installed. Also xboxdrv is recommended often. I tried installing it but as it seems to me, it is "just" a mapper to those controllers if they are already installed.

Can anyone point to a direction of what i am missing on an lxde installation compared to KDE, which has me running into missing the authorize & trust dialog?

If not, is there a way to run just one single X application (self developed interface) inside of KDE and disable about every single part of it to spare some RAM (filecrawler/-watcher and stuff like this).

I really appreciate any help since i am stuck with this since weeks now.