Is the coil outside unusually hot or is the fan outside not running well? It should be moving a lot of air, not like a jet but not like a warm fart either. If that’s the only problem then you’re in luck.
You said there’s cool air from the vents but less than you expect… less cool or less air? If the blower motor isn’t working right that’s a fix you can do, you’d just need a new one of the same motor that is in there now. Then it’s just a few bolts and screws, maybe a few wire nuts.
Is there icing up anywhere? Particularly at the coil inside the furnace. You may need to turn off the power and open an upper panel to get access to see. If that’s happening then the other guy is right and you’re low on refrigerant. A combustible gas tester is not super pricy but even if you find the leak you won’t be able to fix it yourself.
Good luck.
Nonsense. You pour two fingers and slam it then immediately shotgun a beer. It’s the only way.