Are we talking about shot glass, juice glass, coffee cup, 16oz tumbler, 1 liter water bottle that you’ve lost the cap to, or 64oz AM/PM jug ?? (with ice or without?)
At this point, just stick with your one card.
In general, credit scores will be helped by using more cards with amounts spread out, and more positive accts to report.
“Paid As Agreed” on time etc, is what helps scores.
It doesn’t usually factor amounts..
A late minimum payment ($25) is as bad as a $200 late payment, Late is LATE. 3 on time payments are better than 1 on time payment. I’m guessing that your credit score is fine anyways.
I am an affinity credit card junkie also.
If you really want to play the game, opening new accounts to get the bonus offers can be sweet, with the first year often free, and bonus miles and more free trips faster.