It's funny how Thanos easily took out the Guardians with the reality stone on nowhere but struggled on Titan.
Difference was... the Guardians was Quill (who is a human with guns) Gamorra, Mantix and Drax. None who have any type of long range fast attacks or strength to really go toe to toe with Thanos
On Titan it was Spiderman, Ironman, Dr Strange..... that alone is 3 guys that have ELITE LEVEL SPECIAL ABILITIES or EQUIPMENT. Then add on Drax, Mantix, and Nebula.
It was way more for him to deal with.
Also we have to take in consideration that on NO WHERE, Thanos was already there and ambushed the Guardians.
On Titan, all them was already there to prep for him and ambush him. Cuz remember when he first got there he only saw Strange and was assuming it was just him.
Dont you remember his surprised reaction when Strange said "our will"
(timestamped)
Martha