Team Cap -Vs- Team Iron Man

Who wins?
No prep..
No B.F.R..

Team Cap

Cap.America
Blue Marvel
Scarlet Witch
Sasquatch
Captain Britain
Hank Pym
Cls.Magneto

Vs

Team Iron Man

Black Panther
Hulk
Dr.Strange
Iron Man
Black Bolt
Reed Richards
Beast

Team Tony

No....
Without prep Reed and BP are basically useless and high end street leveler respectively.
Beast is strong, but again, prep would maximize him.

Team 1 has more characters that can be effective on the spot.

But team 2 has Dr. Strange. He could solo both teams if he brings his A game.

If is the word though.
Using your line of thinking Pym could shrink everyone down to a fairly useless size.

Still, it IS your line of thinking and perfectly valid.