Hey there. Sorry for late reply.
I read your comic and so far, so good. I really like the vintage aspect of it like old super hero comics from the 70's.
Here's what I suggest to make a stronger character:
Read mythology. Most comics about superheroes are based off of mythology of some sort. Greek and Norse are most common in superhero stories, because often times there are heroes who despite everything, do the most daring task that no one wants to do. Courage is a key trait in a hero.
But this hero has problems of his own. What trauma did he face when he was young, and why is it showing up again? This is something you need to keep in mind. Do not just simply talk about his trauma, show the trauma coming up again and again in flashbacks, maybe when he's fighting a villain, he sees something that reminds him of the trauma. At the beginning of the story have little triggers that show up everywhere; people or things that remind him of something bad. Keep doing this until everything escalates. This will add suspense to the story.
An example of this is the film 'Ghost in the Shell (1995)' about this android who's a cop. The main character is human, just with a cyber-body. As she goes on a quest to defeat the villain, Puppetmaster, there are little reminders everywhere that she isn't really human. When she finally meets the Puppetmaster he tells her the truth that she's trying to avoid; she's always wanted more human traits.
When you character is going after villains or on quests, he is trying to avoid a truth. Eventually, that truth will reveal itself, and when it does this is when your character will be at his weakest.
You are the writers, so I can't tell you what to do but these are just some things to keep in mind.
Good luck out there! ^^