I think in most states ANY felon can vote either immediately after release or at worst after completion of probation or parole. No waiting period required.
About 10 states reinstate conditionally based on the crime.
I think 2 (Kentucky and Iowa) only reinstate based on an individual petition.
Once a sentence is complete all rights should be restored-—ALL of them. If the laws were limited to what they should be and sentences that were appropriate were actually served none of this woudl be an issue to being with.