Steps for turning a separation into divorce

Location: New York
I filed for separation last year using one of those legal document prep places. In the terms, I included a debt that I had paid that the ex was to pay back to me as well as returning some personal property. They signed the documents agreeing to the terms, docs were filed and finalized a bit over a year ago.

I had heard that this can be transferred directly into a divorce by filing somehow online, assuming on a NYS legal site. I’m not in a financial position to hire an attorney at time or I would. I really just want out asap but don’t want to just walk away from the money owed back to me and my property given back. Honestly, the terms were beyond fair given the circumstances.

My questions:

1. The ex has not attempted to fulfill their terms of the separation. I do not know where they are nor have any contact information. Do any modifications have to be done to the separation agreement due to this or will they carry over to the divorce?

2. If the terms carry over, at what point do I take further action to make sure the terms are met and what should I be doing?

3. I have researched several NYS websites and not sure I’m seeing exactly how the process works converting the current agreement to a divorce

4. I’m fairly confident at this point they do not have possession of the personal property any longer. I’m not sure how to proceed there.