Ask HN: Basic Systems Coursework as an eventual tech founder?

Hi! I am a 30 year old SWE at a FAANG company who didn't do an undergrad in CS. While I enrolled in Algorithms, Databases, ML etc. when I did my grad schooling, I never did any systems coursework. As a result I feel like I have some gaps in my understanding. The gaps are in the following areas:

1) Systems - I don't truly grok multithreading, multiprocessors etc let alone operating systems (which I am not super interested in)

2) Networks - My knowledge here is superficial

My ultimate goal though is to start my own company as a technical cofounder.

Questions I ponder about:

1) Do you recommend I enroll in systems courses? I plan on taking these online at a university and expect to spend the next 6 months on this.

2) If my goal is to start a company, why bother? I should start working on ideating, building, iterating etc. Coursework will only push me behind on my goals

I have enough time outside of work to dedicate to one of the above options aka formal coursework v/s working on a product. What does the HN crowd think?