Currently looking at getting started with a side hustle business ,currently considering either dropshipping or crypto trading

I was wondering how important SEO really is? I try to make that work all the time but at the end I am not sure if it really works. if i put tags on videos without making the SEO first it doesnt do better or worse than the others (they kinda all do bad lol) some youtube "gurus" even say don't use tags at all. so I am curious how many of you do all this extensive SEO work for each video or other content you create like posts, blogs or so?