https://www.modix3d.com/tech-spec/
7-inch Duet3d touchscreen – integrated with the controller
seems to suggest 7i, so should perhaps use PanelDueFirmware-5.0i-7.0i
... but if that is what caused yellowness then I guess PanelDueFirmware-v3-7.0 for a v3 is the next step.
(files will have .zip or .bin extension depending on the release version you need)