This issue is addressed correctly now. My decision to default to 100% scale was not the right call. We now instead default to the system scale. I think I heard everyone’s collective “duh” emanate through the Internet. My decision was influenced by testing done on FHD displays, UHD displays were not accounted for. I’m sorry about this folks.
You can delete the PLEX_SCALE_FACTOR environment variable now. Scales of 100%, 200%, 300% will work perfectly. Intermediate scales (ex 125%, 250%, etc) will round to the nearest 100. The rounding is unfortunate but not nearly as unfortunate as minuscule text.
Please update to v1.1.0.