As per my experience, I would recommend you to join Engineering(CSE). It'll provide you with more essentials than B.sc in Computer Science. You can definitely take up M.sc IOT from either paths.
If you want to complete early then go for Bsc
Else would recommend Engineering.
Both paths are good to what you are looking for.
It's your choice to learn more and explore about IOT.
You'll just obtain few important basics and ethics from UG course which aren't enough for the further future.
All the best!!