As a Toon Link player the one thing that I could suggest is, like others have pointed out, LEARN TO POWER SHIELD CONSISTENTLY. This is vital because not only do you not get hit, it will pressure a projectile-heavy character to try to change up their game, or they might become impatient and try to approach a little bit, which you as Charizard can punish extremely heavily. If they stay patient and continue to pelt you with projectiles as you power shield most of them the best you can really do is try to find a pattern in what they're doing, find a way through it and what you should do when they land or shoot their Arcfire or Boomerang or whatever. Getting in close will cause most of the projectile zoner types to get uncomfortable and act improperly, and even if they don't their best option is usually very predictable and often punishable.
Power Shielding out of dashes can be tricky as projectiles are flying at you so I wouldn't worry about that quite as much, but shielding out of your dash should be the main way you approach these. You can try rolling occasionally but they'll be able to punish you if you do it too much. Approaching from the air can circumstantially be better and it's good for mix-ups sometimes, but Charizard is a pretty big target and doesn't move all that fast so trying that too much won't work too well either. Since you're relying on shields a lot you may want to be wary of grabs, especially Robin's command grab Down B since that has a pretty good range, so you also might want to work on reading those for when you get in close.
Finally challenging projectiles with Charizard's fire can work nicely at times, and Down B has super armor that can help cover a lot of options that these characters have up close. Side B will travel across the screen and through weak projectiles so keep that around for every now-and-then. Charizard is a very punish-oriented character, and the best way to get punishable options out of these characters generally is to approach them like this, just don't try to pull the same ideology off on Captain Falcon because approaching him with shields is not something he has a problem with =P