Systemd kills script started by Plasma

I’m trying to have Plasma start a script on login. I’ve tried both adding it as a login script and as a program in the autostart settings. But soon after it starts, systemd says “start operation timed out. Terminating.”, and kills the script along with all its subprocessess (going straight to SIGKILL no less.)

Or are scripts not supposed to be able to be persistent? Programs added from the application list are allowed to persist, and adding a script creates a .desktop file in ~/.config/autostart/ with no obvious difference.

Operating System: openSUSE Tumbleweed 20230703
KDE Plasma Version: 5.27.6
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.10
Kernel Version: 6.3.9-1-default (64-bit)
Graphics Platform: X11
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 62.7 Gibyte of RAM
Graphics Processor: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2
Manufacturer: ASUS