I mean it's a lot of work. And broadly speaking, you're more likely to get negative feedback than positive. And more often than either of those, you'll be ignored entirely.
What's your motivation to set aside 3-300 hours writing something up?
Ask HN: Is maintaining a personal blog still worth it?
https://news.ycombinator.com/item?id=42685534
Why I still blog after 15 years
https://news.ycombinator.com/item?id=41646531
Advice for a friend who wants to start a blog
It's like any other hobby. You do it because you get value out of doing it. Making money is irrelevant. Actually, I take that back... making money would reduce the value of doing it because as soon as your goal is to make money, you're immediately constrained in terms of what you can do and how you can do it.
I like to share what I've worked on. For example, this is something I did with no monetary gain and it wasn't work but I think it was cool and was worthwhile: https://blog.jgc.org/2024/09/cracking-old-zip-file-to-help-o...
On giving back - Throughout my career I've read tons of blog posts that have given me the information I needed to get started or un-stuck on a task. I hope when I write about things that someone out there may wonder 'how do I X?' and my blog post shows up when googling.
On giving insight into myself - I've had people reach out while I was doing a job search that said they looked over my blog posts and that gave them a positive signal which led them to reach out to me for a position.