Hello
I am running the latest version of pi-topOS on a Raspberry Pi 4 inside the pi-top [4] and encountering an issue when connecting an external HDMI monitor. 
The display either flickers intermittently / goes completely black after a few minutes; even though the monitor is fully compatible & works with other RPi OS builds. 
I have already tried different HDMI cables; disabled screen blanking, and checked power supply stability. Interestingly, the flickering stops if I disconnect the pi-top [4] screen entirely & use HDMI alone so it seems like conflict between dual display handling in pi-topOS & the Raspberry Pi’s GPU memory allocation. 
Checked Use my pi-top as an external monitor? Power BI Course Online guide related to this and found it quite informative.
Is there a recommended configuration to force HDMI-only output or adjust GPU memory split for smoother external monitor performance? A config tweak or boot overlay might solve this, but I haven’t found official guidance on multi-display behavior in pi-topOS.
Thank you !! 