Did I read this right that http1 was with cdn A (unnamed?) and http2 was with cdn B (cloudflare)?
If so, you really can't draw any conclusions about the protocol difference when the pop locations, network designs, hardware and software configurations could easily have made the kinds of differences you're seeing.
By not moving our render blocking assets like CSS, JS and fonts over to the http/2 we rule out performance changes due to improvements to head of line block.
Our images were always on a separate hostname so the DNS lookup over is the same. We also did some initial benchmarking and found the new CDN to be more efficient than the old one.
If so, you really can't draw any conclusions about the protocol difference when the pop locations, network designs, hardware and software configurations could easily have made the kinds of differences you're seeing.