Has your startup been successful doing all the coding, design and marketing yourself?

I am a solo founder like a lot of you and my background is a web developer and graphic designer for over 20 years, so that is totally my forte, but when marketing comes around it's a tough game. I am getting early positive SEO markers, Google is picking up a lot of my content and ranking them slowly. I check search console for new keywords Google is ranking for and create content around that. I have been working on back links and staying on top of keeping fresh content.

How successful have you all been with just sticking with totally SEO driven traffic or did something else really trigger a lot of traffic and signups? I am still early on, so I am just seeing how SEO goes first with marketing plans coming up.