@Sala the site looks really good, I must say. It’s also very responsive. And, I can definitely align with your experience of SEO on Flarum. As an ex user of that platform, I landed up with exactly the same issues in the sense that no posts etc were being indexed.
Since moving to NodeBB, I’ve not had any issues at all. In fact, with almost zero effort on my part, this site is being indexed frequently and it takes literally just a few hours before posts appear in Google’s search results.
I think a lot of people are being drawn in by Flarum only to realise after significant investment that it has a number of pitfalls and insurmountable issues. One such show stopper for me was the complete lack of GDPR functionality.
Since moving out of the Flarum ecosystem, I haven’t looked back.