Would anyone know of a good and reputable resource or platform to learn and execute investing / buying  mortgage notes?

I don't know the details, but Cross Country is a reputable renovation lender, and has the VA product.

Meanwhile your peers who own $100K houses in Detroit (no knock on Detroit, just used for illustration purposes) feel the need to create a convoluted web of entities and ignore most of what I shared.

They can network effectively with placement agents - Agents are going to be the primary way a house is filled, so a reputable manager likely will have multiple agents who are willing to work with them already because they have a history of running good homes.

Tenants all tell me they'd much rather rent from an individual landlord, the big PM companies have bad reputations apparently.

When exploring financing strategies for your first BRRRR project, especially with an owned property, start by researching reputable private or hard money lenders who specialize in rehab financing (like us :)).

I would suspect you would be better off talking to a reputable turnkey provider.

There are companies that sell turn-key rentals that could be a great solution for a busy professional, or maybe finding a reputable wholesaling company or realtor to help bring you deals to leverage your time better. 

Steps to Vet a Hard Money Lending FirmReview Their Track Record:Look into the firm's history and reputation.

It's not a waste of money at all if you choose a reputable company.