Am i fucked?

looks crazy but cut to the chase. I got quoted 8k to replace the whole left side of the car meaning the door, quarter panel and trunk because the metal is too thin to weld and bondo will crack overtime. Were the bullshittin? Also i need to know if im better off trying to do this myself with bondo or should i let the professionals fix this.

Im a diesel mechanic but i have never done bodywork before. If there are any shop recommendations or if you know someone that could fix this for cheaper in the austin tx area lmk.