The biggest pro of using FHA and conventional financing is you can easily use them to house hack for 3-5% down payment which is an extremely low down payment. 

I've now used it twice.The program requires 10% down, must be a rental, no PMI, and has a very high standard of credit.Last I did it (Summer 2022), my rate landed in the low 5%.  

There are builders that are offering really low rates.

Ebooks, podcasts like @Bonnie Low suggested and start running numbers on every deal you see until you know how it all works.

I work with a ton of new investors as a realtor the #1 way to get started is just find a 2-4 unit in decent shape and buy it low down with conventional financing 5-10% then you can live in it for a year and do another next year.

Rents are low and prices are high.

If it discharges 5 foot from the building and there is a low spot running back to the building, then it is going down hill back to the building.

Since moving into another fixer-upper isn’t ideal right now, consider leveraging your $40K for a low-money-down investment, like house hacking a small multifamily or using creative financing (seller financing, subject-to, or partnerships) to avoid tying up all your capital.

I'm not in a huge hurry as the cost of holding the property is low, so I'm taking my time to learn as much as I can and connect with the right people. 

Maybe with a low (70% or less) LTV or an ARM and stellar credit...also depends on what type of loan you're looking for (nonQM or conventional Fannie/Freddie)