Talkyard deals with spam by 1) letting you configure manual review of the first N comments, say first 3 comments, by a new user. If someone posts 3 on-topic comments, then likely s/he is not a spammer and no need to review, thereafter, unless flagged. And 2) Akismet + Google Safe Browsing, optionally. (I'm developing Talkyard, https://www.talkyard.io/blog-comments )

For high traffic websites, simply the task to review new comments by new users, can be too much work. So needs to be combined with something automatic like Akismet. Based on what I've heard.