A third-party upscaling tool created by a Chinese developer allows any Windows game running at a lower resolution in windowed mode to upscale to native monitor resolution using an early implementation of AMD's FSR technology. Users have been reporting decent levels of upscaling and increased fps though at the cost of increased frametimes, latency, and CPU usage.
https://www.notebookcheck.net/Magpie-allows-AMD-FidelityFX-Super-Resolution-support-in-any-Windows-game-not-really-as-good-as-native-FSR-but-seems-to-get-the-job-done.553404.0.html