CloudFlare via Webhost (Ionos): Can I manage directly through CloudFlare account?

My website lybrary.com is hosted by Ionos. I am using CloudFlare through Ionos. They offer it as an add on. That is working fine so far. However, their management console for CloudFlare is horribly limited. There is very little one can do. No page rules. No pausing of the CDN, limited reporting, etc. etc. So my question is: Can I manage my site through a direct CloudFlare account even though I have signed up and use it through Ionos?

If you can change your name servers at your domain registrar, then you can go direct with Cloudflare. Just make sure you completely disable the Cloudflare setup at your host first.

Well, I thought about that but there is one problem. I would like to use RailGun. But I am on a managed server where I cannot install RailGun. However, Ionos provides it for managed servers when one uses the CloudFlare service. So if I understand this correctly, I am locked in to using CloudFlare through Ionos if I want RailGun.