What is the purpose of the drivatar sync I only get 3000 credits for 3 drivatar races.
Well, one purpose I found was the little reward I felt whenever I “sync 100%” a track and circuit. And it does give your friends a chance to race you on those newly synced tracks.
But it may not seem to have a big effect on your daily payouts. Those seem to be somehow “normalized” to pay out 2600 to 4000 per day most days, more when your friends are racing, up to maybe 11K per day.
The sync is all about how much like you the drivatar races - has no effect on payout but affects what he looks like to others, and how he behaves on each track.
I wouldn’t complain; didn’t play for a few days and found I only got 17K for 160 races… That’s about 10-fold less than what you got 
You only get one days worth each day you log on.
It does not accumulate. Read the message you get regarding the drivatar payouts.
I know that, sorry if I didn’t make that clear. OP gets 3000 credits for 3 races so averaging 1000 credits per race. I got just shy of averaging 110 credits per race on my Drivatar payout.
I am not complaining or anything; just can’t comprehend the maths behind it since I get messages from people saying my drivatar is sooo quick (for them) which makes me wonder how it still manages to only get 100 credits per race