How many startups is too many startups to be involved with at a time? I will not promote

As an entrepreneur and founder, ideas just seem to keep flowing and with the help of AI it’s never been easier to formulate an idea to get to where you need to start doing the leg work for customer discovery and validation. I have one main b2b SaaS vertical startup, at MVP and will be validating shortly. It’s getting some of my time and a lot of my free capital. It’s my biggest passion. But i have had some ideas spin up before and after founding of that company i would like to pursue. For background i already run a lifestyle company in the industry of my primary startup. Some of the others are completely different b2c and different industries entirely. Some complement the main startup. Has anyone founded multiple startups at once? I mean if Elon can do it right? Lol