It's really a strange thing trying to even finish a project you've already got in the works.
I have my Key to the Void project that I've been trying to get out for 5 years now, having gone through a full reboot at one point and is now at a state where I need to edit it in order to get it to a state in order to get through book 4.
So, it had essentially stalled out. In that time, I was faced with a dilemma. I could keep pushing through and edit it, or I could put it into a state of indeffinite hiatus and start another project.
You can think what you like, but I selected the latter, and I'm quite happy with that decision right now. The new project I still have unreleased is turning out incredibly well, and I'm looking forward to when I have it ready for public release. Sometimes, it's important to see a project to completion while pushing back all other ideas. Other times, you need to shelve a project in order to put effort into another far better idea that has developed from the benefit of all the experience you've gained from working on your current dead-end project. Mulch the old project and use it as fertilizer to better grow the new one.