User experience is always at the whim of ISP agreements unless you are paying for point to point links. Sounds like you're experiencing vagaries of somebody (m

User experience is always at the whim of ISP agreements unless you are paying for point to point links. Sounds like you're experiencing vagaries of somebody (maybe Cloudflare, maybe some other ISP Cloudflare is peering with) doing traffic engineering, probably to reduce congesting on particular paths. The recommendation to go with the Pro plan is likely just the first step, the next step is to open a ticket and get them to fix it -- that's what you're paying them for. Dropping Cloudflare is, of course, an option as most of the security stuff they do can be handled by competent security folks, but you (may?) need to find someone similar if your site is at risk of DDoS.