I'm a member of one locally, and it's a great help to find recommendations for trades and cleaners. 

Patrick, if you use a SDIRA, don’t you have to put any cash flow from the investment back into the SDIRA or face tax consequences?

Do you want to trade up at some point and buy a larger multifamily.

Consequently, I have unintentionally acquired all of this relevant real estate knowledge and experience with marketing, construction, and pricing (at least doors/millwork/hardware/windows).

I am currently a commercial plumber and have been in the business/ trade for four and half years.

It took me a number of months but I eventually found a few underwriters who agreed to trade a bit of their wisdom for an hourly rate.I offer 1-on-1 guidance not because I plan to get rich (I didn’t take a gigantic leap into full-time investing only to give myself another day job)… but because it’s something I wish I had.

I read Eric Martel's, Stop Trading Your Time for Money, and became interested in real estate.

If you're going to college or trade school all of your funds should be going towards that. 

First I should ask if you're a general or trade specific contractor. 

You can also look at private non-traded real estate like BREIT from Blackstone.