I have chronic uti can only pee max 300ml average is 150ml. can bladder recover to full capacity?

Depends!: The longer capacity has been reduced the more difficult to make gains. It should improve though!

Depends: If you used to be able to urinate more and now you urinate less, a urologist might be able to diagnose your problem and provide treatment then you can recover to the previous capacity. If this is a congenital or permanent issue, it might not recover.