By the way… The DNS provider isn’t Cloudflare, or at least not Cloudflare’s hosted DNS service.
It’s DigitalOcean, which uses Cloudflare DNS Firewall.
Trying myself, i think the DNS service is having trouble right now. Some queries work, some queries return SERVFAIL, regardless of record type.
I’d guess it’s a problem with DigitalOcean, or maybe Cloudflare’s DNS Firewall, but who knows.
Edit:
DigitalOcean status doesn’t show any problems right now, but they did have a similar-sounding DNS outage a week ago.