Your title got my attention, it seems that you have failed in promoting using only one channel.
You have to understand that if you are blogging to make money, you have to target lower competition keywords and deliver on the search intent for those keywords.
This way, you will have, as a baseline, some level of search engine traffic.
Now, since you are focusing primarily on promoting on forums, the best piece of advice I can give you is to not post the link to your blog posts.
People will see that as spam.
The key here is to actually help people with their questions.
This means not linking to your website, not mentioning your website, and just simply helping people get ahead based on the information you know.
Once you've developed a credible reputation as an asset to the community, people who may be interested in the overall themes that you talk about, in this case, CRO or conversion rate optimization, would see your biography link or your signature and then click through.
That's how you play the game on forums as well as Facebook groups.
You have to demonstrate your willingness to help and the value of the information you share freely.
This is especially true if you plan to generate traffic from Reddit.
Simply dropping links and moving on doesn't work.
That is a surefire way to get banned.