Actually, it depends on how CF is setup on your site - if it is setup in a too high settings, it can affect SEO in a way. Eg, there is a CF setting that prevents access from a certain country, for legal purposes. So if banning access from a certain country to your site, there is a possibility that the spiders from that region will also be prevented access. That will somehow reduce your organic traffic in the process, or having crawl errors on GSC, which sends a signal to big-G that your site is problematic, etc, and the list goes on. So bottom line - it depends on how CF is setup.