As I play a game on a controller, KDE’s screen energy saving kicks in as if I wasn’t doing anything; as if the controller inputs weren’t registered. What can I do for them to be registered ?
For now, I’ll temporarily disable the setting while I play
You are not alone. In fact, the linked duplicates shows that this has been a long standing (next year would mark its 10 years anniversary) issue. That gamemode that @bogdancovaciu mentioned is a temporary workaround, alternatives are in the linked bug report, read through the comments.
I used to have this issue with some games back when I used macOS, so when I ran into the same issue on KDE I looked for a similar solution and found caffeine-ng in the official repositories.
It’s a small system tray app that can be configured to watch for certain processes and disable energy saving and screensaver when they’re running. Or you can just right-click and do it from the popup menu, still easier than going into KDE settings.