Saitama's TRUE Power?

I'm kinda new here and I discovered some interesting Manga over the past weeks. One thing that got my attention is a superhero by the name of Saitama, or you may know as The One-Punch Man. I decided to read the Manga and really enjoyed it, but it got me wondering, how strong can/will he get? He's seen to withstand almost anything, so I just wanted to talk about him. Do y'all think he will be a formidable opponent to superheroes like Superman, Shazam, or Wonder Woman at the end of the series? Do you think he'll become evil at some point and be as powerful as Galactus by any chance? I know some of these ideas are a little far fetched to some of y'all, but it's a thought that I wanted to start on this website.

He doesn't need to get stronger ....he is already the strongest. Call it what you want-magic , coincidence....divinity. It's just it. He one punches everyone. No matter who or what it is, one punch is all it takes..always. Buuuut, I still don't know if he can hold his breath for an eternity. If he can't..then vacuum of space is his weakness

Is it a good manga? It would seem like trying to read a manga about a guy that overcomes all his obstacles with a single punch would be kind of underwhelming since you know he is going to win every time, and with one punch lol