I cannot comment on the closed systems, as I have not used them, but I do think that WordPress is a viable option.

If you just want to write and for the writing to be seen by Google, then you really do not need more than a couple of plugins and you should have a working blog that you do not need to spend any time on maintaining.

I would go with GeneratePress - https://wordpress.org/themes/generatepress/ and its companion plugin GenerateBlocks - https://wordpress.org/plugins/generateblocks/ for some simple blocks to design the blog. Both of them are well-coded and fast/lightweight.

In addition to them I would use SEO Framework - https://wordpress.org/plugins/autodescription/ as the SEO plugin and you are set. Just set everything to auto update and there should not really be any issues.

No affiliation to any of those plugins/themes, but have been using GeneratePress, GenerateBlocks and GeneratePress Premium for years and not one update has broken anything for me.

FWIW: I started a blog/website on neocities.org a few months ago, and found some webcrawler blockers- at least a couple dozen there at the time, but they needed to be uncommented. So I am using them to block the various crawlers, presumably. I still have not put that to the test. By deactivating the blockers, and checking the site traffic states, one might be able to determine whether they are working or not. You might want to build a test site to try yourself. Neocities is free for up to one GB of space.

Years ago, I used google blogspot quite a bit. After every post was published, the first hit came from a server in Germany. Maybe a mirror or surveillance bot? I'll never know. But sure, it's a little spooky to be training AI with every post, and not knowing whose AI, and it's annoying to not be compensated. I've trained a lot of technical people over the years and it paid well. With the AI we get nothing.

Hey if you have enough interesting material, why not write a print book?

I know, have been there. Another reason why i got a little away from substack is the trap towards vanity metrics sometimes. With notes etc its kind of becoming like a social media platform. It has its pros/cons. For some usecases, substack makes sense. But for my personal writing and more, i have been using bearblog which is amazing

What makes you think Medium and Sub stack articles aren't in Google? Medium ones are, for sure. I have a couple I've written that are top search results for their topic.

https://medium.com/@mimixco

I have been considering Ghost for these sorts of reasons. Pay for convenience knowing you can fall back to open source if needed.

Substack isn't invisible to Google. Not sure why you'd assume that.

WordPress is fine but if you want to primarily focus on content, try Ghost.org. I think their editor and design options are superior to WordPress.

You could always use ghost. You can still self-host it, but they have gone the direction of substack alternative these days.

You say newsletter but you describe blog. So which one is it?

Given you go on to mention Substack, I will assume you are talking about a blog, so no e-mail is involved.

Well, I have created Gethly.com platform, which is what you are talking about, but the Google thing will always be a problem for paywalled content, by nature.

You have to pick whether you want audience or customers. If you want to build a brand, pick audience and write content freely and fully available to anonymous visitors and focus on SEO. In such case your own blog and domain will be the best solution, as you have everything fully under your control. Using Wordpress, or another SSR CMS, will be the best for indexing and search engines to process.

If you want customers, there is multitude of paywall platforms for it, you just pick one and that is about it.

But in both cases, the actual writing part is the least important one as you need to also put on the advertising and marketing cap on and do the actual work - lure in customers/visitors. You have to be a salesman first and foremost, no matter which approach you're interested in. This is what people don't get. They think they are this unique eloquent content creators that out of nowhere thousands of people from all over the world will flock to their page. Well, no. That is absolutely not how this works. You will need to put months and years of work and hard labour to get your name out and attract users, somehow. So, be ready for that and good luck.

Lastly, soon I'll be releasing a new feature for Gethly - paywall as a service, where you have full control over your content as you can host is outside of the platform, and Gethly will just handle payments+access to your content, giving you the best of both worlds. So, stay tuned :)