A few career mode questions

[Tr3m0r]

This is the first time I'm playing 2K outside of just messing around in single player quick matches. It's definitely a lot of information to ingest for my career and my team.

I made a player that I would like to respec or start another character but don't know when or if I should. I'm a 93 and the time to get to 99 is crazy. I heard that rebirth is an option to start another player but does that freeze my current one so that I cannot progress him any further? My player has like no perimeter defense and is basically a midget since I used my own height of 6'1 and cannot rebound anything. I'm seeing just playing the temple and dunes games that I'd have no shot using this character against other people as those ai matches were not that easy for me!

So I don't know how rebirth works and if anyone can recommend a meta build for me that would be appreciated. I'm just super new to nba2k games.