It's a great achievement to take prepare a demo and participate in Next Fest. I really admire your effort. I fully understand how hard is to polish a game.
Marketing is really hard part IMO it's mostly based on luck.. it's sometimes matter of one short on TikTok to let your game be found by a big content creator. What you can do is just help your luck by doing what you described. I am glad you decided to learn more about it.
I really like you noticed to speed up the gameplay, it's a pretty good direction. That's harsh true that I struggle - When core gameplay is not enough "fun", above layers (UI, UX, Music, Story) doesn't really matter, there is no point to polish them when foundation is not attractive for players.
Side note: Good UI, UX as ready to use systems matters because you can reuse it for different games. So it matters from an architecture perspective.
What really resonate for me from Chris (https://howtomarketagame.com/) is quote: "We are making a fuc*** video game, it should be exciting!". That's marketing view on a game, excitement makes ppl want to play your game. What means a game is exciting? I am not sure yet.
I played your demo and enjoyed it. When you release your game I will buy it to support you.