pfSense Fallback

I just moved from the US to Sweden. In the US, my pfSense NextDNS settings were stable and worked 100% of the time. Now that I'm here in Sweden, I find that my internet is relatively unreliable, and I have trouble resolving DNS when using the officially supported NextDNS configuration for pfSense.

I'd prefer to be able to resolve NextDNS whenever possible and fall back to my other DNS servers if a connection cannot be established to NextDNS for any reason. I'm not entirely clear how to accomplish this, however.

Can somebody help me configure my pfSense router to connect to NextDNS with fallback DNS to my non-secure DNS provider(s)?