Both of these are the answer to "stop paying GoDaddy". They differ in what they're willing to do for you.
Cloudflare Registrar sells domains at cost. Not discounted the first year and marked up afterwards — at wholesale, permanently, with WHOIS privacy included and no upsells. The catch is that it exists to keep you inside Cloudflare: you must use Cloudflare's nameservers, the TLD list is limited to the ones they support, and there is no domain-registration API for the general case. It's a loss leader, and an unusually honest one.
Porkbun is a real registrar with a real product. Wide TLD coverage including the niche ones, honest pricing with free WHOIS privacy, free SSL, email forwarding included, a proper API for programmatic registration and DNS, and support that answers. Renewal prices are slightly above wholesale, which is what it costs to run a business that isn't subsidised by something else.
If you have a portfolio of domains parked long-term and they're all on Cloudflare anyway, transfer them to Cloudflare Registrar and save real money every year.
If you register domains programmatically, want unusual TLDs, or want nameserver freedom, use Porkbun — the price difference is a few dollars a year and you get an actual product for it.
Many people use both: Cloudflare for the domains that matter and never move, Porkbun for everything else. That's a sensible arrangement rather than indecision.