With regard to equity, I wouldn’t join a startup unless it’s cheap for me to buy the options. If you get your cliff, and it costs 50k to buy your options, you are sol. You options are to throw away your equity, or be stuck at a shitty job. Whether it’s worth it “to get rich”, is kind of a bs argument. If the opportunity exists to be a founder go for it, if not take the next best possible option.
And tax wise it can work out better as you don't pay income tax of the shares sold to buy the others - this is scenario dependant.