You need to understand why you are "lacking" in marketing or sales.
I know a lot of engineers who internally just despise ads, promoting, outreaching, pitching, etc, but they will say they "suck" at marketing. Most of the time it's not a skill issue, it's the personality and mindset.
It's definitely personality-related. I know people who can sell a potato as the most amazing food ever, and they seem genuine about it. I can't do that with feeling like I am cheating the other person in one way or another. I can only sell what I sell, I can't promise it will change your life, because I know nothing can guarantee that.
You might need to reframe things a bit. Marketing isn't just sales and making the world feel like a Ryanair checkout experience. A lot of it is just about bringing up something people want at the time when they need it.
In many cases, you find your target market, find someone with that market as their audience, and partner up with them.
A few examples: a web dev partnering up with a designer whose clients always need websites and apps, a travel insurance company partnering with travel blogs, a health insurance company partnering up with relocation consultants.
I know a lot of engineers who internally just despise ads, promoting, outreaching, pitching, etc, but they will say they "suck" at marketing. Most of the time it's not a skill issue, it's the personality and mindset.