With some help with redditors and some of the advice on this page, this game can work near flawlessly at 40hz with an excellent battery life for an MMO.

Here are the steps I did in order to get it fully working (even though its listed as unsupported):

1. Install the game (internal drive preferred for the quicker game file check at the beginning of each session in the launcher) and launch the game with Proton Experimental and the above launch commands. It will most likely crash on its very first launch but it's fine, launch it again. Im sure the "WINED3D" one is not needed for this step but I left it as is.

When the DCUO launcher finishes checking and installing the recent patch, the green play button will pop up. Do not click this and instead close the game, it's time to switch Proton versions.

2. Switch to Proton 5.0-10 and remove everything but the PROTON_SET_GAME_DRIVE=1 launch command. I had issues with the other commands when using Proton 5 but that might just be my SD.

3. Launch the game again, leading to the reinstallation of some Direct X install script stuff. This will take a while but when its done, you'll be back at the DCUO launcher. Press play when everything is patched up and a redistributable installation will pop up. Use the touch screen to install this and youll be good to go right after.

Optional: I highly recommend capping this game at 40hz and using the SD frame limiter. It feels smooth enough and the battery life can be upwards of 3 hours, depending on what you do of course.

Setting it to the native SD resolution 800p may look weird at first but it eventually fixes the UI so it will never be an issue. I set all the settings to max except the effects, which I have just a notch below max and its near flawless. There is the occasional stutter when loading new things but the more you play the better it gets. The camera may also feel a bit laggy at 40hz which can be remedied by going 60 but it's perfectly fine for me.