As a hobbyist developer that has been trying to make a game and giving up when I can't figure a thing out since checks notes 2001?! 😢... Listen to these people saying to limit your scope! It's difficult to find that sweet spot of simple but interesting enough to finish for me but it's so important to LIMIT YOUR SCOPE.
Take your big idea and start chopping pieces off in your head and keep cutting it down.
At the moment, I've been on and off on a top down shooter like Vampire Survivors, I have this grand idea where it's a space combat game where you move a giant fleet of capital ships that are driven by a flocking system. It's a cool idea but too complex. I need a simple thing first and then add onto it. I've removed ALL of my spaceships in the fleet down to one guy, all of my gun types beyond one, removed all of the enemy types beyond one, simplified the upgrade system to something that just makes number values go up (Like HP, Weapon Dam, Defense, etc) instead of complex bonuses. It's still hard, it's still boring at times and I'm currently in a trough of disillusionment about the whole thing so I haven't touched it in about a week. BUT this has had a better chance at completion than anything else I've done.
Found a good pic of the process on the company's website, looks very cool