New to SEO - seems like a full time job - any ethical hacks or suggestions?

I have built a Shopify sports equipment brand using 100% paid traffic. When I was researching similar companies recently, I realized that a lot if not most of their traffic comes from organic search. Now I’m learning about SEO but the more I’m learning the more I’m realizing that this is going to be a brutally time consuming process. I have paid for some services on Fiverr in the past but they probably did more harm than good. Friends, do you have any suggestions about how I should proceed? Learn SEO optimization and DIY the whole thing, or is there a better way? TIA