Around a month ago I noticed my passenger headlight was out. As I swapped the bulb it continued to not work so I assumed it was a problem with the ballast. I ordered new ballast for both the passenger and driver side (the driver side's headlight was dim so I believed it was going out) Once I installed the new ballast on both headlights it seemed to work. A week after the installation I noticed the passenger headlight didn't automatically turn on (I had to go on the off/on motion for it to work (EDIT: off/on motion once and it would work for the duration of the car is on).) I just ignored it as I didn't have time but another week later the passenger headlight went completely out and would not work. I checked the headlight fuse because why not and I noticed the IPDM for the passenger headlight had a 20W instead of a 15W. I instantly swapped it but no luck it still doesn't work.

Tonight (about two weeks after the passenger headlight went out) I was on my way back home and my driver's headlight started flickering and would go out. I would have to do the off/on/off/on motion to even see. Does anyone know what could be the problem with this as well as the passenger headlight being out? Thank you in advance. This has been very frustrating for me as I would be getting constant headlight problems.

Check the headlight ground wire, in the engine bay on the front of each wheel well is a single wire landed on the wheel well. Unbolt them, clean them with a wire brush including the bolt itself, apply a little electrical anti-oxidation grease then put it back together.

Since your ballasts have been replaced recently I'd suspect the lamp, especially with the multiple strikes it was taking to get them to fire.

Or buy a single headlight and a single ballast, use them to swap components out until you figure out exactly what parts went bad. It's a lot easier to do when one side is still working since you have known good parts but that doesn't really apply in your case.