So things that are a red flag for me may be fine for someone who's more aggressive.

Potential opportunity - there is an attached utility closet that I believe could and/or used to serve this purpose as it has the red/ blue inlets built into the wall next to a hot water heater that is also in the closet.

Pay it but if it happens again it's on then because you just cleared their line...unless its tree roots or the main line has a rare blockage. 

There are lot of companies you can use to do them; Red Star, RentPrep, Cozy, etc.

I have a property outside of Austin, TX that is slightly in the red each month and looked into 1031 exchanging into a DST as well but ran into some debt replacement issues.

Any gotchas or red flags I need to consider?

NYC is such a tricky market with so much red tape around everything it definitely makes it challenging.

As for your experience contacting agents directly, the market is red, red-hot right now.

I would rather put my money on red or black.

Branches or roots of trees, bushes, or plants on neighboring property.A landowner has the right to demand that the branches or roots of a neighbor's trees, bushes, or plants, that extend over or into his property be trimmed at the expense of the neighbor.A landowner does not have this right if the roots or branches do not interfere with the enjoyment of his property.Acts 1977, No. 514, §1.https://law.justia.com/codes/louisiana/2022/civil-code/artic...Also see here:  Dealing With Neighbors And Trees