Founding engineer 8 times. 5 exits(2 sold shares back to investors, 2 acquihires, 1 acquisition). Never really made any significant money. I would make 10x more if I spent same time at big tech. Milage may vary but my 2 cents if you want to be entrepreneur or work for a startup:

1. Enjoy the process (You can push harder and longer if you enjoy what you do and at the end it won't matter if money doesn't come because any time spent enjoying what you do is already a win)

2. Work with people you like (For founders: don't be single founder, 90% of the times single founders either don't know how to share or no one wants to work with them)