Thank you so much! I can’t believe I didn’t think of that!
I managed to solve the other issues in my own way.
For anyone who has the same issue:
Blurry sprites/textures: Fixed easily by setting filtering to Nearest (under Details–>Texture–>Advanced)
Collision layer showing in tilemap: Set the alpha of the collision layer to 0. This way it will be transparent but still, allow collisions.
Increased gamma/bloom/brightness: Automatically fixed by setting the filtering to Nearest. I am guessing that this was a product of the blurriness somehow.