The default Adwaita skin? There's a Adwaita skin I made here:
https://yabb.jriver.com/interact/index.php/topic,106397.0.htmlIt's not the dark version though (I can't recall if Fedora uses the light or dark Adwaita), but the light version.
MC uses its own system for window drawing and has its own skinning system and it's not really possible to change it to allow native controls, decorations and whatnot without rewriting parts of the app, which could take a year or two. The only way to accomplish a "native" feel is to create a MC skin based on the operating system/desktop environment/theme you're using. I've done some, I have plans for more, but I have little time to do them.
P.S. The window lagging thing is a known thing - If I recall correctly it happens more/worst when using a Nvidia GPU with the Nvidia proprietary drivers. Even with an overkill system, parts of GNOME are pretty laggy even with a higher-end GPU and high refresh rate monitor due to how it was developed. Hopefully that changes in GNOME 4 if they ever get around to beginning development.