Hello.
I'm well experienced with YouTube SEO and would be more than happy to help you optimize your channel and get more out of it. Is your title good enough? Is description descriptive enough, yet similar to your title and tags (which is important for YouTube search indexing)? How many tags do you use on each video? First few are the most important and should be used for non-generic words/terms, while having your full channel name as one of the tags helps with video suggestion to other YouTube viewers. Those are just a few things I would look into, make necessary updates and make sure you get more out of your channel.
Throwing money at Facebook ads and other paid marketing is a terrible idea if videos and whole channel are not optimized properly. However, it may be necessary down the road, but it all depends how big your channel is right now and what are your long term goals.
Kind regards,
Tomislav