i used to implement my physics in my platformer game(posted here on itch) and it works, but it feels too hard and requires time to master jumping skill, so that's the reason why i look for something better. I could use Box2d, but it's overkill for platformers with simple physics.
https://github.com/Astroloico/JetJumper
Here it is :)
There is also an explanation of the games structure in the README.md file beccause my code is pretty messy ;)