Your numbers actually tell a better story than the empty comment section suggests. Two hundred weekly visitors against 100 members means a lot of people are finding the subreddit and reading without joining or posting, which is normal for a small community. Most people lurk first, and they only comment when a post gives them a clear reason to.
That is why I would be careful with the fake user idea, even though I understand the temptation. Nikolaos is right that Reddit picks that pattern up fast, and once a subreddit gets flagged it is hard to rebuild trust. What worked better in my experience is posting one thread a week that asks a real question people in your niche are already searching for, not just news or links. Something like a problem they ran into, a choice between two tools, or a mistake they made. Then answer the first couple of genuine comments properly, because that back and forth is what turns a lurker into a regular. It is slow, but those are the members who actually stick around.