Pygame platformer collision issue when moving horizontally as cause of phasing trough the tile

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Python

Describe the problemI'm having trouble with my python platformer collision logic, i've recently started following tutorials of a youtube creator for pygame platformers. And had no trouble in making a platformer until the collision logic. I tried to perfect my code but i'm still having issues;
For example:
1. When i move in any direction while on top of a tile i phase trough the tile vertically.
2. When i land on top of a tile the feet of my character get stuck a few pixels inside the tile.
3. (Not really an issue) I have no idea how to write jumping code, i tried changing the Y Velocity to -5 and then the game glitched out.

My goal with the collision logic was to stop the player when colliding with a block, to be more specific when colliding with a side the player stops.

Project File: https://github.com/1NilusNilus/Pygame-Platformer

Movement code for the Player:

def move(self):
    print(self.VEL)

    self.RECT.x = self.POS[0]
    self.RECT.y = self.POS[1]
    self.POS[0] = self.RECT.x
    self.POS[1] = self.RECT.y

    self.POS[0] += self.VEL[0]

    self.VEL[0] = 0
    if self.DIR["left"]:
        self.VEL[0] = -5

    if self.DIR["right"]:
        self.VEL[0] = 5

    for tile in self.TILE.testCollision(self.RECT):

        if self.VEL[0] > 0:
            self.RECT.left = tile.right

        if self.VEL[0] < 0:
            self.RECT.right = tile.left

    self.POS[1] += self.VEL[1]
    self.VEL[1] += self.GRAVITY

    for tile in self.TILE.testCollision(self.RECT):

        if self.VEL[1] > 0:
            self.VEL[1] = 0
            self.RECT.bottom = tile.top

Collision Code for the tiles:

def testCollision(self, rect):

        self.RECT.x = self.POS[0]
        self.RECT.y = self.POS[1]

        hitlist = []

        for tile in self.TILES:
            if rect.colliderect(tile):
                hitlist.append(self.RECT)
        return hitlist

What I have tried:

I have tried rewriting the code multiple times, i have tried watching the tutorials all over again, i have tried asking the web questions and researching.