While some services support payment in crypto, be advised that there's no such thing as complete privacy on the internet.

Three letter agencies will routinely run TOR exit nodes and monitor traffic. You can be profiled merely on your browser configuration and usage behavior (eg mostly posts during daytime in specific country), sentence analysis and words you use. A determined government actor with unlimited resources will be able to track you down sooner or later. They did find Silk Road creators, albeit it took them years.

That being said, tails + tor is a good option. Maybe over VPN so your ISP can't see you're running tor. Run it from USB if possible, that can be quickly discarded. If possible, do not use the computer for anything else - hardware can be fingerprinted. Use a static site generator (such as Hugo). Host your blog on IPFS. Try not to have predictable patterns / times when posting. Run your text through a local LLM to change the words and sentences.

If you opt for a commercial service, find one that accepts payments in Monero, which is completely private.

Other than that - good luck.