While I can certainly sympathize with the concern, the reason nobody has answered is fear of an angry response, which is frequent in such a situation. Hopefully not from you.
So…Cloudflare expects to be the one and only DNS for your domain. It looks like you can use Cloudflare as Secondary DNS, but still use the proxy service. I think this requires at least a Business Plan. The trick is that your DNS records point to Cloudflare proxy IP addresses, so you’d have to to a mass-switchover to not use the proxy IP addresses.
There’s also the option of becoming a Cloudflare Hosting Partner so you can use your own DNS that’s tied to Cloudflare DNS. I expect this would still require a mass-switchover to origin IP addresses.
Again, I get where you’re coming from. Things are going to break and you don’t want to be affected by the outage. Stuff somewhere always breaks and ruins someone’s day. And then they curse and scream that they’ll never use that product again, so they switch to another product. That will also definitely break at some point.
So…weigh your options. While yesterday’s half-hour outage was a pain, the worst part for me was not knowing where the problem was. Cloudflarestatus didn’t show anything, and I couldn’t reach any other part of Cloudflare. What I appreciate is that every time something at Cloudflare breaks, we get a thorough explanation of what happened, and what they will do to stop that thing from happening again. This isn’t an easy operation behind the scenes, so I’m definitely appreciative that it works 99.99% of the time.