Another alternative is contracting. Those who hire contractors usually don't have the manpower to test extensively, and they're more likely to trust you to deliver. Or not care that much because you'll be working on a non-core element.
I had the same idea about startups but have failed numerous technical interviews for positions I was probably overqualified for. Even asked a few for accommodations for my ASD/ADHD in testing but no go.
Some have a loose idea of what they want but need someone to guide them on what is or isn't possible. There's room for mistakes, and some flexibility.
I know about HN's "Who is hiring?" post but I'm interested in other sources too.
Same meat grinder approach to hiring a perm.
Many are those are dead end projects that never get off the ground, or don't have enough budget for a marketing team and a full MVP. Many are part time founders who make good money and want to throw money at a side project, but aren't fully focused. There's a lot of downsides to the path too.