No. Assuming this is a full-time position in the United States, $22K is well below even internship compensation.
You have many more job opportunities available to you. You need to put yourself out there and find them.
Prepare your resume today. Start applying. You're not obligated to accept the other jobs, but you'll never know unless you put yourself out there. Don't delay this.
> How can I negotiate a (much) higher total compensation for myself?
Interview at other companies. Secure job offers with higher pay. Accept the job offer you like the most.
If you really want to stay for some reason, you could use the competing offers to try to renegotiate with your current company. However, make sure you have good reason to stay. It's difficult to rebuild a relationship like this once you've reached the point of feeling cheated by the founders.
> but I've discovered they've lowballed the lead frontend engineer also (<0.5%)
If the lead frontend engineer is receiving a market-rate salary, getting 0.5% in options isn't actually a lowball.
The unfortunate reality of startup equity is that there isn't much to go around to non-founders who are collecting salaries. Offers above the 1-2% range are usually reserved for VP-level positions and higher. Equity in the 10%+ range is only really seen for cofounders, once you factor in seed stage funding.