to be fair, anyone who doesn’t follow the card game mechanics could easily just assume the difference is card layout or some other mechanically irrelevant thing. no shame if you simply don’t follow those sorts of things.
one of the virtues of e4 is people learning things about aspects of the hobby even if it’s something as inconsequential as why some letters are capitalized and some aren’t.
Im kind of glad you posted this though, i have been playing tcg for a few weeks only and i was curious. The more you know! Thanks for being so cool about it.
the main difference is that (little) exs can evolve. Charizard ex evolves from Charmeleon. However, (big) EXs are always basics. Charizard EX does not evolve from Charmeleon. Of course, once Megas were introduced, EXs could evolve into M EXs, but that is a generational thing. not so much a mechanical thing specific to the suffix.
To make things even more confusing, exes from 2003-2007 are still labeled by PSA as EX just as they do for the 2011-2016 EXes, but the new SV era exes are labeled correctly as exes.
Do you know the difference between capital and lowercase E in the the English language? Can you see? If you answered yes to both questions then you too can learn the difference.