There is a middle ground between building it from individual cells and buying an overpriced system from Jackery. Buy solar panels, charger, battery, inverter separately. You weren't going to build solar panels and a charger from parts. A Tesla battery has a professionally engineered battery pack which very rarely catches fire. ICE vehicles probably catch fire more often. DIY batteries catch fire much more often. Beginner DIY batteries are just about guaranteed to suffer a few shorts during or after construction. A 200Ah battery will make a huge fire very quickly if shorted.