Private room needed (San Francisco)

Seeking a private room for myself — Professional city worker in my 40s.
I’m a single male no pets, I don’t drink, smoke or do drugs.
Currently in search of a temporary room for the next 3-6 months as I navigate the process of purchasing a home.
My work demands long hours and I’m doing online school in my free time.
All I require is a secure and tranquil place to rest.
Thank you for your consideration.