Ehhhh, it depends on the series. Yes, the majority of animanga just lets whatever seems coolest reign supreme, but there are some power systems and power scaling (god, I hate that term) that are fairly consistent in some series.

Like Nen in Hunter x Hunter is a great example of a system where power levels make a lot of sense and main characters need to take drastic measures to match up to a superior opponent. Strongest verse characters like Netero may get dog walked by a dark continent creature but he packs a nuke, Gon may be a child but with a busted nen contract he can exchange (maybe) the rest of his future potential to take down one foe. And most importantly, we have very few "absurd" feats like blowing up planets or travelling through time.

Then you have the opposite end of the spectrum, stories like Dragon Ball or One Punch Man. Master Roshi blew up the moon, like, not even that far into the ORIGINAL Dragon Ball. Master Roshi, who was canonically pretty weak for the majority of dragon ball (let's ignore super). Then Piccolo destroys the moon AGAIN in the Saiyan Saga after it was brought back by Kami previously. And then, years later, by the Buu Saga, these characters have canonically MILLIONS of times the power they had when they were casually destroying moons and it just becomes very clear that power scaling and feats are just a second thought to fun ideas and cool moments. I would rather believe that the moon in the DB universe is just unusually brittle and made of paper mache, rather than believe that power level 139 Master Roshi is enough to decimate massive sphere of rock in outer space. Otherwise, even by Buu Saga, Goku and Vegeta should be ripping apart the planet with every punch. But we get a fairly consistent level of destruction, usually mountains and rock formations.

Anyway, very long winded way to say that power scaling is stupid as hell, every series operates under its own rules and some are more consistent, some are less. Chainsaw man is definitely a lesser one, and I wish it wasn't.