> I.e. my understanding is most devices are not like the 3s lipos I put in my hobby robots, but instead have integrated charging circuitry that you just give an appropriate voltage to... and that proper charging behavior avoids a lot of the dangerous scenarios with lipos?

I'm not sure your understanding is correct. There are assembled packs with a BMS on them, laptop batteries this is usually the case. The cells themselves can be lipol, prismatic, or cylindrical (like 18650's). The cells almost never have active BMS built-in. It's always external (either on a board on the pack or on the device itself charging it).

I really think the battery fires are mainly qc issues and running bad qc cells beyond limits (either fast charging or discharging). If capacity is staggered a ton between cells then even charge balancing the cells isn't going to do much good. Pouch cell fires probably more related to physical damage due to expansion in places they aren't designed well to expand (so it pushes the jellyroll down and causes a short/thermal runaway).