When they nearly had the glove removed from Thanos while hypnotized, why didn't Dr Strange just make a portal and close it off on his arm...chop it off. Or someone else just chop the arm?
Also, what are Dr Stranges limitations? Why not a portal thingy and go right back to earth from that planet...why were they stuck?

Dr strange seemed strangely underutilized in what could have been.

Also underutilized:
Why didn't Wanda or Marvel simply take care of Thanos right after they regathered after the "rain fire" order? Like, just quickly take him out.

Why doesn't Thor bring lightning down on Thanos in a steady stream... over and over? Just keep doing what works best.

Okay...Preppy...it's not real. Gotta make action sequences entertaining and not simply have the obviously most powerful characters quickly take care of business.