Nobody can wall that off behind a paywall.
Nobody can put a popup over your stuff and say “Don’t look at the content right now. It’s so much better if you login!”.
Nobody can build their brand off of your work. Nobody can make money off of your work, if you don’t want to.
Nobody can tell you “You can’t have your own domain on here.”
Your hoster will most likely not suddenly go: “Oops we just went out of business / were acquired, we’re deleting all your stuff but you can export it until tomorrow and fuck off, basically.”
And if they do, you can go and host that somewhere else.
You can still decide to re-distribute your content to places like Medium, dev.to, Micro.blog, Twitter, Instagram, Linkedin, Facebook and / or via a newsletter. It’s a good way to extend your readership.
You can have an RSS feed! That feed should always be under your domain!
Writing on the internet under other peoples / companies domain names is like giving away money.
Sure, sometimes it makes sense to guest-post on somebody else’s blog because it broadens your audience. That’s a good trade-off.
You should just always have a place that people can come back to that is yours.