You will likely give up $10's of thousands of dollars by doing so.Once it is vacant, make minor repairs to ensure everything is neat and functional, give it a fresh coat of interior paint, then polish everything including the windows!

When we purchased our houses (July 2022) on a small interior lake and just the frontage was worth $650 per linear foot!

If it were mine, I would (probably) make the interiors up-to date modern so that it is not super obsolete looking in 10 to 15 years.I would do them as they turn--one unit at a time--and spread the financial hit out over time (both the added turn time and the added out of pocket).I would also check the water heaters for age (service life) too, as well as doing any electrical upgrades when the walls are open (adding additional GFCI outlets or etc...)My rational about this is would be, can the place get market rate rent simply by painting over the paneling (which seems low end to me), and what is the close in competition offering and getting in rent?

No need for complex interior architecture.

You only need to deal with interior items in your unit.The bad is the hoa and how they are managed.

Do you do your own interior design for flips or hire a designer? 

A little bit about me, Ive been doing interior design for several years, with my focus being on investor buy/flips and STR.

Anyway, the interior looks great.

Purchase price: $32,750 Cash invested: $5,000 small single family that we ripped out interior and remodeled / upgraded.

Renovated the interior and exterior of the homes.