Sounds like you're doing the right things.

I guess my only advice would be, to really try to put yourself into the mindset of the potential audience. And think of yourself as someone that knows nothing about the page, but sees the thumbnail or advertisement for the first time, and try to picture what they would think.

As you've discovered, there's a little bit more to marketing than just showcasing a product. There are a lot of additional factors such as the quality of the thumbnail, the quality of the page, the quality of the product, whether the product gets word-of-mouth advertising, whether there's an element of luck, etc.

You should have a site that search engines can index, not just a Discord server. And you should talk to people right here in the community. Simply talk to them, don't just promote your own games. Show some interest in theirs, too.

itch.io does a pretty good job directing peeps to your stuff its self..., just make sure to have the appropriate tags. Most of my traffic are just from the tags alone, :3