All I can say is that I am very happy I added a compressor to my setup even though I am really skeptic at first. It creates so much possibilities with pneumatic tools. Just get the one with decent capacity to handle your air hammer’s needs.
Don’t take the risk dude. Ngl, garage doors are extremely dangerous and finicky, even pros can get it wrong. I agree with User3, just hire pros that can handle this type of jobs.