Two things come to my mind, are you aware of the necessity to relax and take your mind off of things to work efficiently? "Spare time" is essential for working, and in some countries you are prohibited from working on the side for that reason.

How do you feel about your side projects? Do they help you take your mind of work, or are they more work? Don't feel bad about not progressing with your side projects, if they are hobby. For me, some side projects were relaxing and helped me to disconnect from work.

My advice, limit your working hours. Your side projects count as work, if you they feel like work to you. If they relax you and you look forward to it, do them when you feel like it. But try to be honest to yourself about it. No need to impress someone with your "work-ethics", not even yourself.

People are bad at multitasking, you might overload yourself with things to keep in mind. Schedule time for wrapping your work up in writing, so when you finish for the day/week/... you are finished with it, until you pick it up again.

Prioritise: What is the point of multiple side projects?