I'll just throw in what I know here:
First of all, all your characters will be "you" to differing degrees. Even if you don't straight up share their personality, the way you present them in the story reflects your views. Your own experiences will flow into them, and main characters especially tend to represent something vital to the author. That's why they're the main characters! Creating a character from nothing without putting anything of yourself in them is, as far as I'm concerned, simply impossible. I believe that's how flat cardboard cutout characters happen -- look at movies where minorities (PoC, women, etc.) are shoehorned in. They're not characters, they're pure tropes and cliches.
Now the execution varies based on what kind of story you're writing - an autobio comic will by nature straight up feature the author! But if you're aiming to write a decent story, and you want to make a character similar to yourself, what you should be vary of is creating a Mary Sue. In other words, you make the character pure wish-fulfillment, free of flaws, because you can't distance yourself from the character enough. (My personal fear, tbh) But as long as you make sure to give every character motivations, fears, flaws, redeeming traits, and a proper character arc, you shouldn't have to worry too much. If you're still feeling unsure, find a trusted beta reader!
Now for an example of both personas and basing characters on yourself done right!
(Osamu Tezuka's Black Jack, what else would I bring haha /is smacked by people sick of my Tezuka refs)
Black Jack, the grumpy genius surgeon without a license, is a kind of wish fulfillment for Tezuka, who gave up on becoming a doctor and became a comic author instead (and aren't we grateful for that). He never lost the wish to help people the way he wanted, outside a corrupt medical system.
But at the same time, Back Jack is very much his own character, and a very complex one at that. That becomes even clearer when Tezuka inserts himself into the comic as a doctor(!) and directly interacts with him. It's not frequent that Tezuka shows up, but when he does, he might do it in a more serious way, here as a friend, helping the plot along: (Tezuka is the one with the glasses)
Or in a funnier way to break the fourth wall for comedic effect (he even brought in the editor too):
Basically, you can insert yourself however you want. Just make the characters interesting people.
Edit: Holy shit this turned into another long post. Back to studying...
Edit 2: What happened to the pictures? D: