Not siding with the contractor, but as an investor you will have to learn to understand costs better and when it doesn't seem possible for the contractor to complete the work at the stated quote its best to walk away.

Let's clarify this real quick,I understand this model wouldn’t work for every property owner, especially those who are looking to sell outright and walk away from the property entirely, and the approach isn’t designed to replace a traditional property sale. 

My client bought a 22 unit building and used this strategy and walked out of closing with a check for $800k to perform the rest of the renovations, paid himself back his already expended rehab costs and his entire down payment.  

When is the last time you did a walk-thru (highly recommend taking a video!)?

You want prospective tenants to come see it, walk it, imagine living there so don't get in the weeds on the details or offer photos that aren't great. 

Obviously the end goal is to build my own real estate portfolio, but gotta learn to walk before running and crawling before walking.

They seem to be walking back.

So yes, I guarantee we will see people selling as-is and walking away. 

Run don't walk

I say this because your opening post was like walking up to a buffet and asking the chef if you should have pizza, sushi, ice cream, scallion pancake, spare ribs, or peanut butter and jelly.