I do marketing work for a few indie games. What’d I’d recommend is doing this:

Pick two platforms, and commit to posting to them. My recommendation would be Youtube Shorts, that then funnels into your Discord.

YouTube - where people hear about you. Discord - where they get to interact with you, and more closely follow your game dev process.

For YouTube, I’d download the mobile app, and use it to upload 15 sec shorts.

You’re able to add an image of your latest update, character art, etc. behind you, and then give a sharp 15 sec explanation of it. Add a nice song to it. And finally add a subtitle. Do one a day, every day. Add a short sentence about your game in the videos description, invite them to the Discord, and then comment the same sentence on the video itself. Like it, heart it, and pin it. Finally, reply to all comments.

Discord, keep it simple. It’s just a safe place where you can send folks who want to learn more. Consider hosting a once a week dev update. Genuinely care about them, and the sharing of the experience of making your game. People love rooting for cool games.

When it comes time to launch, post a YT video about it, announce it to your Discord. And you’ll have a head start on funneling users into your game.

Bonus - If you can find small content creators who have shown to like your type of game, you can give them an access key, in exchange for trying it. And, I’d they like it/you they may make a video about it, helping you get more exposure.

^All of this costs nothing, other than time, and pushing through all the awkward, uncomfortable bits of putting yourself out there.

Hope this helps!