@hnb That is very different to wanting to cull inactive users from your list. The only options for that appear to be:
Dive into each user you follows recent posts and judge if you want to still follow them
Notice stuff in your home feed that you aren't enjoying and unfollow those users. I use this method.
If the posts I'm not interested in are a temporary topic I'm likely to give them a time limited muting so I can resume reading their interesting posts later.