Mitigation for ddos attack between js challenge and captcha

I’m looking at creating firewall rules for specific countries to mitigate ddos attacks on my site. Which action is more effective; js challenge or captcha challenge?

The last resort for me is to outright block the country but if only i have no choice.

I usually go with JS Challenge because the UX of CAPTCHAs is pretty bad. Only if I get a flood of bots solving JS Challenge would I switch to CAPTCHA. Your Firewall Rules list will show the solve rate (CSR) of JS Challenge.