Earlier quoted context omitted.
You don't need XRay and your reflow oven can be a toaster oven. I do recommend a cheap microscope and a good pair of tweezers though. With this you can do 0.5mm pitch BGA although that is pushing it. I've made hundreds of prototypes this way. The fear of BGA parts is seriously overblown. The only real expensive part is the finer pitch parts will require tighter tolerances on the PCB which will take you out of the PCB…
Your comment reads as if you equate 'BGA' with 'SMD', a BGA is a ball grid array with up to 1,000 tiny pads that have been pre-dipped in solder. Your toaster isn't going to work.
BGAs are SMD (Surface-Mount Devices) for all intents and purposes.
And I've fixed plenty of BGA-mounted GPUs with a Black and Decker 1200W heat gun.