Just jumping in - you absolutely don't need powered USB active adapters to get more than 2 outputs.

https://www.amazon.com/iVanky-Active-DisplayPort-Thunderbolt-Adapter/dp/B089GF8M87

https://www.amazon.com/Cable-Matters-DisplayPort-Supporting-Technology/dp/B00EDSZYII/

Speaking from experience - you can drive at least 6 displays (I think I've done 7 before, also using the built in HDMI).