I personally have made great experiences with the forum. My students really liked it and they picked up how the forum works pretty quickly. In my experience, it is almost even more important to show the students how to use the activity you are describing.
If you want to give your students a few instructions as to how they should create/write these posts so that they are engaging, I can recommend this post: https://www.digital-minds.agency/blog-erstellen/ It is written in German but you can easily translate it online, e.g. with Google Translate and it covers the most important basics.