Be very careful when you feel desperate. It's a recipe for bad decisions.
Long-term: sooner, softer, smoother. Recognizing and addressing issues sooner means you can make smaller adjustments.
Short-term: consider treating your current situation as your role learning experience. If you as a developer don't own the product, who does? Why isn't that you? If you think you can build a business on your own, you should be able to be the product owner within your company (and then you'll have plenty of resources if the product is worth something). If you do that, you'll have the experience needed to head out on your own if that's what you really want.
If you scoff that you could never do it in your company because those roles are filled, it's corrupt, etc., then treat the situation as your emotional learning experience: i.e., even if the company is as bad as you think, assume it's the best opportunity you'll ever get. How can you be the one that spins straw into gold? Build your own agency. It's unlikely you can afford better collaborators on your own dime.
Finally, the value stream always branches and branches. You can always go smaller to avoid competition, or bigger to divide a larger pie (typically into smaller pieces). If you want to extract value. But is that what you want?
If you want to build your brand, create something critical for someone important, retaining the credit and the credibility. For success and satisfaction, it's likely more important whose team you're on than what you do. And for that, you never, ever want to seem or be desperate to leave.
Whether building products for people or working with collaborators, think about things from their perspective: that's consideration (both emotional and as exchanged in contracts). Empathy for others is the master virtue, and you might find it helps you avoid thinking of working for a company as working on something that doesn't belong to you.