Unfortunately, founder-dating is the same as normal dating but probably even harder as the stakes are higher. It's very difficult to find same "motivation-level" people (how much do they "want" it, are they as "hungry" as you, etc.) and it is very hard to gauge with talk as you have to see their actions to really know and sometimes it may be too late. At the same time, there is also the "stage in life" (single, married, etc.) and how much can they risk (like a 45-yr old person may not be able to quit their high-paying job so you will carry the load and end up with a lot of resentment)

Since you work at a FAANG as an engineer, I assume you are fairly well compensated so I suggest finding a semi-expensive hobby (definitely not FIRE friendly) like sailing or flying which may cost like $1k/mo to something you remotely enjoy so you get to meet people from all walks of life and domain expertise enjoying a "not cheap" hobby. The fact that they can afford it means they are motivated. The person doing your hobby may not be the person you end up starting a business with but it may be one-step away (degrees of separation).

This may be bad advice ... so take with a grain of salt :)