Yeah, I agree. “Stuttering” doesn’t sound like a touchpad-specific issue. My guess is there’s something funny about Fedora, either drivers or kernel flags or default plasma settings, that just isn’t playing well with that specific device. I wouldn’t be surprised if another distro magically fixes it.

Edit: Or there’s a hardware issue. Gnome caused the device to grind to a halt?

I mean, you don’t necessarily need a fresh Arch install; I’d wager you could just switch to Arch in place by editing your /etc/pacman.conf and /etc/pacman.d/mirrorlist to Arch repos. You’d probably need to keep a Manjaro section at the bottom of pacman.conf to avoid breaking too many things at first. Is this a good idea? Probably not, but it’d be fun to try.