I could be wrong, but I don't think a naturalized DR citizen has to use a DR passport to enter the DR. I have never heard of that mentioned by anyone until you did.Yes, there's an option for 10 years for an additional fee, but they don't ask you if you want it so you have to ask them.
Regarding biometric chips. They changed the passport book in 2018, but the chip was not implemented. Then they changed it again in a year, promised it to be biometric, 2020 passports look different but no chip again. Recently there were some articles about new biometric passports again, as I understand they changed the passport book design again in 2021, but is there a chip? I doubt it but maybe somebody who got his passport recently can say something.