To get around this restriction, its a good idea to play backup cards that are functionally similar to your win condition
But with counter doublers like Lae'zel, Vlaakith's Champion and proliferate triggers, youll have no trouble turning your 2-drop commander into a board wipe that threatens lethal damage with just one attack
Switching out his background is a shame since Folk Hero works so well, but Raised by Giants is a solid choice to improve the deck's color identity by providing access to green.
Take his first ability which doesnt outright kill an opponent's creature, instead negates most (if not all) damage done by it
We can see the cave in the background of Gustav the Giant Terror of the Kingdoms art
Captain Rex seems like an incredibly unique and interesting commander to build around, and hey, you dont need to know anything about Attractions in order to run him