I don’t think the hcaptcha made that much of a difference, however that together with the watched words and the fact that now all new users have to have their first post manually approved has more-or-less solved the issue.
Looking at the number of posts per-month on the deleting Discourse spam thread:
- 2 Mar 2025
- 1 Feb 2025
- 3 Jan 2025
- 12 Dec 2024
- 8 Nov 2024
- 4 Oct 2024
- 1 Sep 2024
- 2 Aug 2024
- 3 Jul 2024
- 5 Jun 2025
- 1 May 2024
- 4 Feb 2024
- 1 Dec 2023
Things are basically fine now, it peaked at the end of last year.