it’s maybe because you didn t draw correctly the boxcollider , or and that’s more probable, if u used a layermask to allow the player walk on the floor , you have to add the layer to your platform object , or it’s another thing and it will be better that you upload a little screenshot so that’s someone can help you (sorry for my english)
For anyone to be able to answer how to fix anything, they obviously have to understand what is broken. Your post simply does not provide any useful information to understand what is actually happening without many guesses.
Please spend more time providing useful information such as images or video because descriptions like “Player kinda fly” could mean anything.
To echo what Melv said, please familiarise yourself with the Getting started section and specifically the stickied post here. Users and staff will be more than happy to assist you as long as you give context and information.
I recommend editing your post with additional context to avoid any more headaches.
Colliders that involve polygons (anything that isn’t a Circle) always have a tiny numerical gap for stability, They won’t be overlapping perfectly. This is controlled by the default contact offset but don’t go reducing this to near zero for a rendering reason and then get stability issues with physics. Reduce the size of the collider slightly because there’s absolutely nothing that says the physics needs to match sprites exactly.
In the end though, you are free to change whatever you like but be aware of potential stability issues.