That is part of the problem with a lot of companies (I am not knocking insula as dont have all the info/facts just stating how the business works), they engage brokers to get them loans and the brokers collect a small fee. unfortunately many of the brokers may be similar to real estate wholesalers - have little to no experience. 

Even 600k loan at 10% interest costs $165 a day.

I have been doing these type of loans for 30 plus years and buying foreclosures since the late 70s.. seen it time and again  ..

Did you try a local CU or bank for a construction to permanent loan?

With one small exception on VA loans, there is no getting around the due on sale clause. 

Also, with a VA assumable, if the one assuming the loan is not a veteran, then the seller (veteran) entitlement will still be tied up in that property.

This is a large community and someone might give you some insights on the lender or the loan officer.  

@Chinku Chinku how is paying the loan balance down going to help you reach your goals?

Both Conventional loans and DSCR loans can offer this flexibility, depending on the specific scenario and borrower qualifications.

Focus on understanding the rental market, conducting thorough property inspections, and leveraging owner-occupied financing options like FHA loans.