It's more niche than say embedded systems, but you'd be surprised how much there. The chipdesign subreddit is fairly active, but reddit is about to imminently collapse. Edaboard is okay but honestly I find their community and moderation to be rude and unfriendly.
Start up some topics. See if there is enough interest. Then decide.
One of the pleasures of this forum is the eclectic mixture of topics. Splitting into subforums
might have the disadvantage of creating enclaves. Splitting into subforums
unquestionably brings the disadvantage of whether a topic should be in X1 or X2, which is always a pain.
As for edaboard - I was a member for a while, but (like stackexchange) specifically precluding multi-level quoting means the conversations were sterile and boring. OK for "which button do I press to floggle the widget leftwards", but not for the more useful questions about "
why floggle the widget since squirdling is often better".