How long generally does it take for the re-enlistment bonus to process to DFAS once it’s pending review at the state level?

It should take about one month, two at the most. Just stay on top of it in the event you need to poke someone in the eye!

If it is still pending at your State level, it will be a while.
There are two more levels of review after that:
-Camp Robinson, AR
-NGB
Bonuses from 50 states, 3 territories and the District are all piled up at those two levels.
Then it goes to DFAS.

If you haven't already, verify the start date of your new contract.
Often Services Members mistake their reenlistment, which begins the day after their current contact ends, for an immediate reenlistment.
The remarks section of the DD Form 4 should list the effective date of your contract and bonus.