In ~/.config/mimeapps.list you need to add
x-scheme-handler/http=google-chrome.desktop
x-scheme-handler/https=google-chrome.desktopto ensure the default browser (Google Chrome in this case) is invoked
when running xdg-open https://pt2.allsup.co/.
So my mimeapps.list file looks like
[Default Applications]
text/html=google-chrome.desktop
x-scheme-handler/http=google-chrome.desktop
x-scheme-handler/https=google-chrome.desktop