My 2011 Malibu LTZ key fob doesn’t seem to be working correctly but I’m unsure if it’* the fob that is causing the issue. The battery holder was broke when I got it so I soldered it back on. It has a new correct battery. The fob has very short range and I have to pretty much hold the unlock/lock buttons down for a while. The remote start won’t work also. Also the lock/unlock button on the drivers door is delayed, and the passenger side is not, I did disable delayed locks in the settings.

I would get a new fob.

Yup. They're pretty cheap.

Is there any way to program a new one myself or do I have to take it to a dealer?

I believe you'll have to have the right (expensive) tools and training or take it to a professional.