Read up till chapter 13, I would say that time travel / fantasy tags are not that important compared to goofy comedy.
The MC had a beef with the HERO of his world, and wanted him dead. Why, not explained yet. He jumps back in time to his teen years and starts plotting to kill the hero while he's young, but nothing really works for the mc.
Waiting to see what advantage did he get from the time travel, the author tries to paint the MC as smart but without results, I can't see that, though again, the main genre here is comedy.
The art is surprisingly amazing and fits the story. I will put this one on the shelf for the dark days to get back to it, cause it's not in my mood right now.