I am currently using MAC OS High Sierra 10.13.6

Only the three most current versions of macOS are supported, Ventura, Monterey & Big Sur.

Mostly you just need a more modern Browser than Safari on Mojave, or High Sierra like Firefox or Brave.

https://brave.com/

Thanks to dialabrain…

Firefox 111.0.1 is now the current version. runs in High Sierra.

https://www.mozilla.org/en-US/firefox/new/