I've read a lot of LitRPG books, and a few of them have unique leveling styles, although most of them just level in a crazy way, and I don't mean normal level crazy, I mean the type of crazy where the MC's strength stat goes from 5 to 200 by just 4-5 chapters.
I don't wanna deal with this same situation, so could someone help me out here?
How do I write my MC's leveling in a way that he doesn't go from trash to God-like in just 4-5 chapters???
There's a few really simple ways.
1) Make the numbers matter for something tangible. (New or improved skills, abilities, spells, etc)
2) The numbers don't matter. Your depiction of them does. Write them however you want, and assign your own meaning to them, with your own scale for powers or abilities.
Ultimately, the trick here is consistency. Pick the approach that works for you, and your story, and stick with it. The numbers can mean whatever you want them to in the end. After that, it is just a matter of scale and pacing.
For example, if you like Final Fantasy, you can use stat values in the hundreds or thousands if you want to. Or, you can use much smaller ones to convey the same sense of character ability. It just depends on you and how you go about implementing it.
It all comes down to scale and where you want yours to sit.
If an average human has a strength of 5; then anyone with a strength of 10 would be insanely strong. Where if the average human strength is 100, then something with 10 is multiple magnitudes weaker, with the same exact stat value.