I swear, us ultrawide gamers are so neglected it's not even funny. I'm using a G9 OLED ultrawide monitor, and every time I set my windowed games to 2560 x 1440, they either cover the taskbar or the taskbar covers them. I use MS PowerToys to center game applications while they're in windowed mode, and not all my games have this issue, but the ones I frequently play, unfortunately, do. Moving my taskbar to the left seems to resolve the issue, but I really hate the look! Restarting "Windows Explorer.exe" in Task Manager doesn't work, and programs like MS PowerToys and Display Fusion are cool and useful, but are no help either. 

I saw a video of this program (Borderless Gaming) on YouTube and was instantly hooked. You could set custom resolutions to windowed games, make them go borderless, or give them a borderless look by removing application title bars, allowing them to float cleanly without the taskbar covering them or vice versa. So, yeah, I was hooked, as this not only fixed my issue but combined with DisplayFusion's dim mode, would ultimately make windowed gaming look and feel like full-screen gaming, with Discord and other applications on the side dimmed out. Unfortunately, none of this worked or to the extent I thought they would. The program settings would work but then instantly revert back or make the games go fullscreen or other weird resolutions. Again, not all my games have this issue, and I think I'd still use this program if I didn't have this issue. However, I'm going to keep testing some more games in my library, and if both issues persist, then I'll unfortunately have to refund this product.

So, after running more tests, I've finally gotten the hang of things and have fixed my issues. Below is a visual representation of what I was dealing with (with Borderless gaming not running) in a lot of my games, with games overlapping with my taskbar:  
https://steamcommunity.com/sharedfiles/filedetails/?id=3476002939

As I said before, the taskbar issue is now fixed! I really can't express how happy I am to have resolved this issue. Ult tabbing isn't for everyone, and not all games need to run at 5120 x 1440 resolution. Sometimes, I just wanna play games at 1440p in a 16:9 aspect ratio while listening to ESPN praise my mighty Celtics, all while  chilling  waiting for the homies to hop on Discord.
https://steamcommunity.com/sharedfiles/filedetails/?id=3476051532

Lastly, I mentioned before I've also paired this wonderful program with programs like DisplayFusion and MS PowerToys, with the ladder offering a theatre mode, AKA "Monitor Fading." I mainly turn this feature on to focus on different tabs, movies, schoolwork, or, in this case, video games, especially at night when I'm sensitive to light. I also love that this program removes title bars, and of the 11 games I've tested it on, only one seems to bug out after a while (Rainbow Six Siege).
https://steamcommunity.com/sharedfiles/filedetails/?id=3476053262