No pocket listings = agents aren't even calling for new leads anymore, rising interest rate has nothing to do with an agent's ability to generate leads.If you mean multifamily apartments, 5 units and up, some of those agents will know, but not many until you are over 10 units which are more listed by only commercial brokers which I agree do understand seller finance.

I do not see a need for extra cost or tech not all of your guests will appreciate (i.e. older generations).

Here are a couple of developers you should take a look at Trion Properties, their principal Max Sharkansky posts here on BP, https://www.biggerpockets.com/blog/top-5-markets-multifamily-rentals-2019and Feldman Equities out of Tampa (3rd generation real estate family famous for having built the terminals at Chicago O'Hare) who are among the only ones opening up downtown skyrise office buildings to accredited investors.

Purchased and sold on the same day, it generated a $50,000 profit.

The goal is legitimate: due to complex tax rules, you have opportunities to game the system by selling some of your investments and intentionally generating either gains or losses.

I'm struggling to generate extra lead flow from builders, mostly because it's so difficult to identify folks that are doing ground up, business purpose construction. 

We don’t plan to leave jobs and live off of the portfolio but have it as a wealth generator aka hedge against future risks

The answer is to value this as any other business generating income, not just stick within the confined box of valuing the real estate only.  

A $12.5k mortgage is quite steep and ties up a lot of capital in a primary residence, while renting offers flexibility and allows more of your liquid assets to work toward generating wealth.

If I assume this is a rental property, your income isn't over $150k, and you're not a real estate professional then the losses the rental property generates could offset other income up to a certain amount.