I would definitely fire your trainer and replace him with a basic.
I know this isn't what you want to hear but I would also sell one of your stud Cs. Your starting SG has a salary below 4k and you have 0 bench. Replacing one of the Cs with a 15k PF/C (your current backup can start), a 15k defense oriented SG, and some kind of SF/SG/PG combo backup in the 10k-15k range would probably improve your team while cutting a bit of salary. It would also allow your game shape to improve.
You don't have to follow my specific replacement plan, just consider that in general a 20k SG and 25k C are a lot better than a 50k C and 4k SG while also being cheaper (if they are all getting big minutes).