I agree with the sentiment here. It would be really valuable if the Forums lens was a way for me to surface discussions from niche communities like fountainpennetwork etc.
That said, isn't this problem a variant of the reason a separate "Fediverse" lens was created? From this post @Vlad noted that if the Fediverse and Reddit lenses were combined, Reddit would just overshadow all the Fediverse results. I get the problem that no results show up when Reddit is blocked, but even with that fixed, wouldn't niche community results still tend to get massively overshadowed by Reddit?
I would love if there were a way to just have a single "Forums" lens that was actually able to surface quality forum results from around the web in much the same way that Kagi search tends to do a better job surfacing results from the Small Web.