I would encourage you to file a bug report with KDE. If you have discovered a bug, this will give the developers a chance to fix it, thus improving the software and benefiting the whole community.
#2 should not be considered an option. It is forbidden by the Arch LInux Forum code of conduct, see here:
Arch Linux distribution support ONLY #
Arch-based distributions have their own support fora and users of those distributions should be actively encouraged to seek support there. These distributions often use different packages, package versions, repositories, or make custom system configurations silently, practically rendering support for such projects within Arch Linux impossible. Community technical support shall only be provided for the Arch Linux distribution and the Arch User Repository. Posting issues with, and requesting support for, derivative distributions or operating systems other than Arch Linux are prohibited.
If you reinstall your system, try to set it up the same way and see if the issue can be recreated. If so, for sure you should raise a bug report with KDE.