Our lives are very busy. It's easy for those of us unfortunate enough to have a broad spectrum of interests and hobbies to feel like we're mediocre at many things instead of great at anything. Some considerations:
Creating threads of consistency: The "10,000 Rule" says it takes about 10,000 hours (about ten years) of fairly hard-work to become an expert at most things. That means it takes 20-30 years to become an expert at something without working very often. The reason most of us don't follow this approach is because we give up or get tired of relearning what we already worked hard to learn. I want to better learn how to pick-up where I left off.
Learning to learn: There are a lot of resources on learning to learn (Like this one for example). Taking the time to create the best approach and build the best resources before tackling a new hobby or education is entirely worth it and will leave time for other things.
Weekly schedules may not be the answer: I tend to break things up by week. I'll workout twice a week or write a new song once a week. If you have multiple interests, it's entirely ok to spread out the schedule. Again, I just need to take good notes so I can pick up where I left off.