That should be easy enough to solder, the main issue is that 0.5 mm pitch doesn't allow breaking it out on a "cheap" PCB process (like pcbway / jlcpcb / oshpark / aisler). You need design rules that are pretty tight.

I do not entirely agree. I encounter frequently packages that are WLCSP with a 0.4 ball pitch. The pitch is usually not nearly as hard as the routing, so if you lay out the ball functionality cleverly you will create channels for signals to pass through outer balls. They are tricky to assemble, but I still found assemblers overseas happy to do them with so far perfect reliability without much cost. 0.5mm ball grid would be a lot easier though =)

Well yeah, if you sacrifice some balls as "route-through" that changes things. I'm talking about fan-out of the full 7x7 balls with no sacrificed pins on something like 4/4 rules without microvias or ViP (so can't put any via under the chip basically). And you can breakout vast majority of them, but not all. And on 0.4mm pitch is just not doable, with 4/4 rules you can't even get 1 trace between 2 balls without DRC violations. Never heard of that website and it doesn't resolve for me. But I'm not talking assembled in any case. Here I'm talking self-assembly and PCB made in the 20$ total for qty 10 range.

yes, I agree then