If your dead is 300 and your squat is 180, it sounds like your jumping technique is not as good as you think it is. Playing basketball does not help your jumping technique if it wasn't good in the first place it just reinforces whatever technique you already have.
Max squatting isn't all that great for jumping either, neither is atg. There's all kind of programs, 5/3/1 is more for strength then jumping. If your worried about your vertical, focus more in short all out sprints(50meters or less). If you don't want to do that, you can try De'Franco's jump program.
Feet Glued to the floor tends to be slow ankle flexing. Do ankle hops atleast 2 minutes before your workout. Not straight but 4x30 seconds, or 6x20 seconds.
Very Important focus more on the offseason. Your legs will just get tired, and weaker if you do all this plus basketball practice, and games