OP wants to get PAID for their work and rewarded for the all-in effort they'd put in.
re-read their comment
this is why they don’t belong in start up land
running and working in a start up requires a certain type of insanity
this individual is not a fit
If the founder views you as replaceable, then why not work at a big tech which would pay you dramatically more? Successful startups are not often populated by the irrational.