I'm using a combination of Otter and GPT to do most of my long form blog or email writing now. I'm using it right now, and it's quite simple. Basically, what you do is create an audio note. I use Otter, but you can use anything. Then, you speak off the cuff about whatever it is that you want to talk about.
Once you're done, you copy the transcript, paste it into GPT, and ask it to clean it up into paragraphs. Don't ask it to re-write it as a blog post, because if you do it'll probably add a ton of marketing speak. You can also ask it to keep using the style that you originally wrote in, with a similar tone. This method has been super helpful for me. I find it much lower friction to dictate what I want to talk about, like I would be telling a friend, than to type it out. It's also faster. But the biggest benefit, more than the speed, is that the threshold for creation is a lot lower.
One way you can extend this method is by creating two audio notes. In the first one, write out all the things that you would want to cover. Then, in the second audio note, look at that list of things you would want to cover and basically just answer the questions.
This also reminds me of a method that I've used in the past to make writing easier. Anytime you can give a lecture on something, host an AMA, or discuss a topic with an interested audience, you can gather their questions and answer them. This way, you end up with a library of content that, at least for me, is a lot easier to produce than sitting down and writing. But, the library of content can then very easily be turned into writing.
I hope this helps!