I tried the debug steps for GR, but didn’t find anything. This is what the log shows (after trying to install the binary of GR directly).
┌ Info: Emptying depsfile. GR provider is GR
│ provider = "GR"
└ depsfile = "C:\\Users\\my_user_name\\.julia\\packages\\GR\\KPElO\\deps\\deps.jl"
[ Info: Downloading pre-compiled GR latest Windows binary
BTW, Plots and GR seems to work fine in Jupyter notebooks, which makes this really confusing.
ElectronDisplay worked beautifully! I will use this for now.
I decided to delete my .julia folder and install only Plots to check. The plots showed up without a problem! Probably my global environment had some weird conflict from installing and uninstalling many packages.
Thanks everyone for the help! I should certainly learn to keep my global environment clean in the future.