/EDIT/FOLLWUP/Likely Monitor profile problem, see my third reply/
Please post your System Information as Lightroom Classic reports it. In Lightroom Classic, click on Help, then System Info, then Copy. Paste into a reply. Include all info from first line down to and including plug-in info.
Several suspects, one being license status, another being GPU driver (except why working yesterday)
Just another Adobe customer; My Sys; APP: LRC 10.0, PS 22.0; CMP: WIN WS 16GB OS 10 v1909 (18363), mid 2015 MBPr 15” 16GB MACOS 10.15.7; 4K EXT DSPY; CAM: Canon 5D Mk III, Fuji X-T3