Am a youtuber and am trying to get the difference between the two which one is better to invest in as a young Nigerian youth trying to make a living from it.....pls I need ur opinion

It depends on what you want to deliver to your audience

You can make money from any as long as you have fresh source of content
But I think the YouTube is better, because you don’t know when your content would blow, but I don’t see that happening with blogs

Another tip is, if you want to start any, you should not be thinking of cashing out till like a year of putting out active content, because you have to reach a requirement before your account can be monetized, for youtube it's about 4k total view hours and 1k sub I think, I'm not sure. which would roughly take about a year of posting content, that's where most people give up. If you want to cash out faster, I suggest you buy a monetized youtube account or you buy the one that's closer to monetization goals, I mean, just consider it capital, just like buying the camera as well, Another thing is most youtubers open channel without knowing the niche they want to talk about, you see then talking about random things in their vlog, you can't really start a youtube account talking about random stuffs, if it were an already established account it'll be fine, That's why gaming content is top notch on youtube, it's always fresh and easy to get content, easy to make, like the way "among us" is trending, Your niche can be Tailoring or something, or tech stuffs or comedy
Good luck tho