I had this problem in my recent search, very similar situation (early-stage startup, then founded two companies).
What yielded success was shooting for "Full-Stack Engineer" and "Product Engineer" roles
Surprisingly, while startups were particularly excited, a lot of bigger tech companies were too
But while shooting for "Product Manager" or "Backend Developer" or even "Front-end Developer" I got nothing, it was the "Full-stack" keyword that got me tons of interviews
What yielded success was shooting for "Full-Stack Engineer" and "Product Engineer" roles
Surprisingly, while startups were particularly excited, a lot of bigger tech companies were too
But while shooting for "Product Manager" or "Backend Developer" or even "Front-end Developer" I got nothing, it was the "Full-stack" keyword that got me tons of interviews