Workaround for what??? You only stated that there's an issue, but have not shown us your issue. The link works for me. see screenshot

Do you have the same issue with Firefox in Troubleshoot Mode? https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode#w_how-to-start-firefox-in-4troubleshoot-modesf5safe-modesf

This is a screenshot of what I get when I try to accessany Tiktok page...

That's much better!!! What security software are you running?

None.

Even after refreshing firefox I am still getting the same error message - secure connection failed.

Wifi or plugged in? Windows home or pro? Can you try booting to safe mode with networking and try again. Also check your proxy settings. see screenshot

My connection settings don't allow me to select the DNS HTTPS options.