This may not be the most recent news, but I just noticed from looking at the github issues section of EXWM.
From version 0.27 alpha-background can be applied without issues (before there were problems with the system tray).
To fix system tray issues:
(setq exwm-systemtray-background-color 'workspace-background)
Now the future seems to finally have proper gaps:
[https://github.com/ch11ng/exwm/pull/858](https://github.com/ch11ng/exwm/pull/858)
Thanks to the EXWM maintainer and contributors!!!