You mixed it, so I split it for you.
Traffic sources
YouTube - easiest to maintain and fastest results
Blogging - kinda outdated as there are only 3 results per keyword; in social media you can get traffic without ranking
TikTok - what is that? shouldn't be legal imo; not because of content, but because of how they operate and treat accounts
Instagram - it's fine if you can do farms of mobile phones
Twitter - it's fine too as long as you know how to monetize it which isn't that easy as even normal girls promote there, and it's one of the most spammed
Industries / niches:
Crypto - quite hard, a lot of opportunity, but what I would recommend is just to hold bitcoin and skip the rest; I heard airdrops automated with bots can make you money. Trading is gambling. Affiliate crypto is hard as clients are usually educated adults, so you need a good offer.
Graphic Design - you can't really be good at it without years of drawing and trying to paint images with perfect alignment; it pays less than engineering and takes the same much amount of time to master; not that lucrative as sales, programming and marketing. I would replace it with video marketing.
Wordpress editing - nonsense, a skill that everyone has. If you think of wordpress development, try engineering without WP - now that's something interesting and can be scaled. If you have some software like SaaS, WordPress is useful to integrate that SaaS into it via Plugin - you get extra clients for low bucks. Just matter of connecting with online API.
This is only my opinion and I have no real insight into any of that. I'm only doing YouTube as you can see - it's the easiest in my opinion.