I realize this isn't for everyone but this is how I got 60 frames per second on Elden Ring, Max Settings, frame gen without any noticeable ghosting or graphical glitches on my ROG Xbox Ally x... So stock windows I was getting around 30fps, max setting in Elden Ring. When I used the program Lossless scaling, setting the adaptive frame generation to 60 fps, I had clear ghosting when I moved the screen quickly. You really need around 45fps real frames to get 60fps with Lossless scaling without ghosting in Elden Ring on the handheld.
So I used Atlas OS which is a stripped down custom version of windows that is more geared toward getting as many frames per second as possible, using only about 1.4 RAM total for windows operations (which is nice since RAM is limited on a handheld and shared with the GPU). They remove the telemetry, bloat, as many background processes as possible. Elden Ring went from 30fps on max settings to 45fps max settings. Which allowed me to set it at a rock steady 60FPS using Lossless scaling without any graphical glitching.
Also my problem with Xbox Mode in stock windows is that it doesn't show games that you installed from a USB and I don't really care about XBOX game pass or purchasing games from their store but both are front and center when I turned on my handheld. So I completely removed their software.
WHY DIDN"T YOU INSTALL BAZZITE??!!! Compatibility mostly. I have some older games that just run better in windows and even using deckyloader in Bazzite/steamOS Lossless scaling can be a little finicky and personally I consider Lossless Scaling to be a must-buy with a handheld pc. I don't like Lossless Scaling's x2 frame setting (ghosting on ROG ALLY) but the adaptive 60fps setting works great and takes care of any dips or stuttering you can have on the handheld as long as you can keep the real frames above 40fps.
WARNING on downloading custom windows versions: I used Ghost Spectre with AtlasOS over it Atlas OS is open source (Ghost spectre is not) so that you can view the code and has a community behind it but you still probably shouldn't make online purchases or set up online banking on any public custom downloaded version of windows. I now use my handheld for gaming and only gaming.
WARNING: Be aware that you will also have to go to the ROG website and reinstall all the drivers/programs that come with the ROG ally. I would download them beforehand and put them on a usb stick
EDIT: I also got rid of Armory Crate and im using Handheld Companion and G-Helper instead. These two buttons have replaced the buttons on my handheld.
There is also a free open source windows program called "Playnite" that you can download that is basically a front end game launcher like Steam Big Picture mode and Xbox Mode. I have this program now replacing what used to be the Xbox mode launcher. It has a lot of user made mods so you customize your game menu to look however you want.