Setting environmental variables for all applications launched in a gnome session

Back in the days I used a tiling WM, I was able to set environmental variables for all applications via ~/.xinitrc or other methods. With Gnome, this method does not work and I need to use systemd’s environment.d, as explained here:

However, my use case is a bit different and according to environment.d(5) I can’t use it because it doesn’t support shell commands. I would like to have the following variables set globally for my Gnome session:

export MPD_HOST="$(secret-tool lookup mpd-host localhost)@localhost"
export GITHUB_TOKEN="$(secret-tool lookup github-namespace doronbehar)"

Putting these lines in ~/.gnomerc doesn’t work, see this thread. For most purposes, I currently have these lines in my ~/.profile so at least my shell knows these vars. However, I have many more such calls to secret-tool for other env vars and I’d like to set them only once, to reduce my shell startup time.