I'm probably a dummy because I've paid for software like Winrar, but I've also paid for a license to a program called WindowSpace - solely for the snapping feature, but I found out it can also set windows to always on top and of course, relevant to this thread, minimize any window to the system tray. So check it out.
Maybe I'm a dumbass, but I bought a Windowspace license instead of allSnap because allSnap was pretty slow on the 64-bit transition back in the day. No problems snapping since 2009 (€24/8 years = not a bad investment).
LG UWs: ScreenSplit (ctrl+f "ScreenSplit")
Other Monitors: WindowSpace
Two programs I could NOT live without for my ultrawide and secondary vertical monitor.
As already stated by others, there is no way to do this within windows natively. There's a few dozen third party tools that can offer it.
There's AquaSnap Window Manager which has been in a bundle of software and can be picked up the cheapest as a paid utility AFAIK.
Then there's DisplayFusion which is considered the best, as far as I can tell. Offers a ton of neat features, but is also a little pricey. I believe they offer a free version on their website directly, which will let you sample it, but it's not free forever with the split-monitor function. This feature in particular sounds like what you want: >Applications will maximize to the size of each split
Both specifically work with Eyefinity to do exactly what you want.
With a bit of configuring, WindowSpace is free(?) and you can set up a keybind to maximize it to your center monitor.
I believe they can do what you want, which is snapping your video to the center monitor exclusively without being true fullscreen (as eyefinity makes all 3 monitors a single monitor to windows, so virtual "splits" are required.) I'm not sure of any truly free softwares that will let you do it, only ones that come with your monitor drivers on ultrawides and such.