Post anywhere you can. I share my stuff on Facebook, on the GDevelop forum (the development platform I have been using), and on a classic Doom forum where they have a section for creative works that aren't doom mods. It isn't a huge amount of traffic but I do get views from all of those sources, in fact I get a lot of people coming from the GDevelop forum even though nobody has commented on the thread itself. So you might want to consider posting on the Unity forum if you haven't already, in the WIP or Made With Unity sections.
The next step after that would be to get into more marketplaces. If you think about it from a player perspective, most people only look at the one or two online stores that they are already using. And for average players that will most likely be the biggest ones such as Steam and Google Play. If your game isn't discoverable on one of those, you're missing out on a big chunk of the gamer population that doesn't know about or frequently browse itch.io.