Promissory Notes - Risks and Benefits

[Vamsi Vikash]

Hello friends, 

I'm brand new to real estate investing. Based on my research, Promissory notes seem to be a good passive income with around 10 - 15% returns. Here are some of the websites, that I've researched so far: 

1) F Street - https://fstreet.com/ - 10% 
2) Norada Real Estate - https://www.noradarealestate.com/real-estate-markets/ - Around 15% 
3) SIMM Capital - https://simmcapital.investnext.com/portal/offerings - Exploring 

I tried to go through this blog - https://www.investopedia.com/terms/p/promissorynote.asp to understand more about the Promissory notes as well. Unfortunately, most investments are $50K minimum, and I'm in my early 30's and still trying to get that much liquid cash to invest. Can experienced investors like you, please share your thoughts, risks, or things I need to be aware of about Promissory notes? 

I'm using this as a vehicle for passive income if there are other options, please feel free to share. I'm already familiar with Stocks, Options, CDs (Ladder), Bonds,..etc. I'm looking for an option that might generate a 10% return with fewer risks (I know I know :) ) if possible. 

Cheers