I had a buddy, whose pickup was beat up bad. His door handles would pull out a little at the button end. They were original doors, but I assume had seen a very hard life. Most of the rest of the pickup had.
Never tried it, but I had thought about using some small square tubing or angle (like what you can get at the parts store or Orshcelns), 1/2" or smaller. Glue it to the inside of the door around the handle with body weld adhesive. Either in a rectangle surrounding it or just above and below. You could even take it a step further and attach it to the opposite inside of the door. Sort of like making a roll cage for the door handle. The expense would be in the body panel adhesive unless you can get a body shop or someone to donate a small amount.
Again, I have never tried this, but had thought it might be something that would work.