A "miserable corporate job to no where" isn't all that bad - health insurance benefits, 401k matching, probably some sort of discount stock purchase plan, stability, lenders like it.

I'm curious what lender would take something that can have swings of 50% on a weekly rate as collateral?

Start running numbers on potential deals to get more comfortable, and build out your team—like a CPA, property manager, and lenders.

Instead of debates and personal opinion, look for proof https://www.ladbs.org/docs/default-source/forms/plan-check-2017/single-family-dwelling-duplex-plan-review-list.pdf under G (Interior Env) which defines the minimum requirement of a habitable room (aka bedroom or bathroom).

WIth the new FHA & Fannie Mae legislation, many lenders are forecasting the rental income from additional units, even if they're not a zoned duplex.

I've used the search feature on this forum but didn't have much luck.Are there any US investors, hard money lenders, or groups that invest in flips outside of the United States, specifically in Europe (Netherlands, Spain, etc.)?

Aim for 720+ for best rates, I suggest start building relationships with your local lenders.

I have lenders in place.

Ensure that you thoroughly review your state regulations and display the necessary notices before changing any locks or removing any items left behind.

A lender that specializes in distressed properties can help you find the right financing for your scenario.The Bottom LineInvestors will find unique opportunities with distressed properties, but the myths need to be dispelled.