When working on multiple projects it’s possible (and likely) to have each project at different levels of completion. While it’s satisfying working on different things at some point it makes sense to finish the first one.
Once you finish the first one, you can set you eyes on the second one, then the third the the fourth.
As you finish each project you get the satisfaction of completion which makes it easier to be motivated to finish the next one.
Have a great day!