One can choose to set FONTCONFIG_PATH system-wide or inside the desktop file. I added an additional sed statement above, to upd-chrome-stable and upd-brave-stable. Here, for Google Chrome.
sudo sed -i 's!^\(Exec=\)\(.*\)!\1env FONTCONFIG_PATH=/usr/share/defaults/fonts \2!g' \
/usr/share/applications/google-chrome.desktop
Likewise, for Brave Browser.
sudo sed -i 's!^\(Exec=\)\(.*\)!\1env FONTCONFIG_PATH=/usr/share/defaults/fonts \2!g' \
/usr/share/applications/brave-browser.desktop