OOOHHH, you're not just using DNS, you're using Cloudflare's premium offering WARP+ -- which uses a feature called Argo Smart Routing. Sorry I didn't realize that at first.
In that case... yeah, you're speed is genuinely affected. You're going to get better speed because Cloudflare is making your connection take a better, less congested and more direct route to the hosts you connect to.
Please point out which result you're talking about. I didn't see any of your recent results with a variance that high.
note: There's a setting in advanced settings to switch that number from variance to standard deviation. Might be the default soon, I like it better.