Cloudflare OS does have the important risk-mitigating feature that you can fork it if the vendor becomes hostile to your interests. You can't really do that with managed services like Workers (workerd exists but isn't a drop-in replacement for the entire Workers platform).
Whether forking is economical depends, of course, on your scale and on how many others are in the same boat.
Whether forking is economical depends, of course, on your scale and on how many others are in the same boat.