Not sure why the process would be any difference for a voucher holder in a duplex or single family.

As an example, our request for rent increase that was submitted in Sep 2023 has not been processed and may never be processed.

I wasn't hoping for my responses to be read as an indicator of making a decision to invest section 8 or not, or stating that I have a more thorough DD process than someone with more experience.  

Give sellers the space to make their decisions without rushing the process—trust takes time to build.Listen More, Talk Less: The best closers are the best listeners.

Nights, weekends, holidays, etc.To keep this on-topic, though...DO figure out what's healthy for you to manage but remember it's a process where every experience teaches you good and bad (and be patient with that process).DON'T sweat the small stuff (damage/costs under $50, undisclosed dogs, etc.) but DO find a way to learn, prevent, put in better practices to maintain your sanity. 

They were abandoned and needed significant work which wasn't a huge issue but in terms of HUD owned properties i heard there can be significant processing periods.

Based on what you're telling me, I'd also advise you to begin the process of evicting/non-renewing the lease.

Some states are easier than others; however, it is important to understand the process and laws of owning properties in another foreign state.

Working with a reputable team can ease the process.

Whenever possible I attend the inspection and follow the inspector as he conducts the inspection and ask him questions during the process.