DNS IPs being shared is not an issue. It doesn’t affect your search engine rankings or anything like that. If it is an issue for you, you can get a
business Enterprise plan and set up custom/branded nameservers (although I believe the IP is still shared with other Enterprise users).
Dedicated IP address space is available on our enterprise plan. Our enterprise sales team would be happy to discuss with you. https://www.cloudflare.com/plans/enterprise/contact/