I'm a seed stage VC. If you want feedback on your pitch or cold email, please email me at leo@susaventures.com. I'd be happy to help.
My fund might be a fit as an investor. If not, then I might be able to suggest a few firms that could be a fit.
Also, 4% is a low open rate, but that might be misleading. For example, I set gmail to not open images by default, which could affect emails that use tracking pixels.
Finally, selling something for $10m+ is a really amazing "last resort." :)