I was a former startup founder and companies like FAANGMULA (Meta, Google, Apple in particular) have reached out to interview me for senior SWE positions, how should I chose any one company (these options or others), that I think might want me to recreate the type of IP that was in my startup paying me a salary instead of acquiring me (if I were to do my company again), which they can cheap out on? If my goal is to have my own company again someday, should I work somewhere else less related to my expertise (just need it to pay the bills for a few years before trying again)? Or do I go somewhere, think I can learn, won’t necessarily get promoted or get paid more and sacrifice my IP that these companies (or other smaller startups), could actually end up owning?
I wouldn't worry too much about IP right now - Just focus on getting a good job, stabilize within it (work 2-3 years), and figure out your next steps from there.
Meta, Google, and Apple are all amazing companies with tough interviews. I would go through all those loops and see what offers you can get. From there, you can make a choice (assuming you get multiple offers). It's also tricky as those are big companies with many, many teams, and Meta/Google have a team-matching component. That will play a bigger role in which offer you take more than the company overall.
In this market, it's unfortunately one where it's less about the engineer choosing the job and more about the job choosing the engineer. Many engineers are only getting 1 offer in this market, especially among the Big Tech interviews they take on.
Companies get bought, not sold.
Is your concern that you're being taken advantage of since you're getting hired as a regular employee instead of getting acquired? This feels like wishful thinking:
If my goal is to have my own company again someday, should I work somewhere else less related to my expertise (just need it to pay the bills for a few years before trying again)?
I'd do the opposite. Work somewhere very aligned with your expertise. (1) learn from the best people, and (2) build your credibility to make it easier to raise money in your next venture.
We talk a bit more about the common path to start a company here: What are some strategies of getting started with Entrepreneurship And Tech Startups?