Surely reading isn't always a bad use of time, as there are an incredible amount of successful / famous people who swear by spending great amounts of time reading (Benjamin Franklin and Charlie Munger, to name a couple). But how much is too much? If I'm spending all of my free time reading, then I'm not spending it doing.
I'm curious to hear how others think about this, as it's something I wrestle with frequently. (For reference, I am a guy in my 20s who graduated from college last year.)
As for technical skills, I think it was Bob C. Martin or Andy Hunt who said that if you read one technical book a year you will be ahead of most of your peers.
My personal opinion is if there is a project you want to work on, do that. But if you aren't excited by anything at the moment, keep reading! Following your passions gives you a deep well of energy and it seems you are passionate about reading, so I'd lean into that and not worry too much about it. Its not the worst thing to be well-read.
[0] https://www.scientificamerican.com/article/novel-finding-rea...
A related problem is how to balance reading the background material with getting started on a project. How many papers should one read in an area before writing their paper? How familiar should one be with a technique before presenting the results to business partners?
It is impossible to be productive at all times, it's very important to have times and the means to relax.
However if you have an objective in mind, and you're finding yourself incapable of doing it because of your hobbies, only then I'd start considering it to be a problem. (It becomes procrastination)
For this next minute, choosing to do anything means choosing against all the other possible things you could do with that minute. You could be working out, learning a new coding language, learning Swahili, learning how to cook, learning how to paint... (Fill in the things that you have at least some degree of interest in doing.)
But there's nothing wrong in not doing any of those things in this minute. There is also value in just stopping, and doing something you find relaxing, fun, interesting on its own (as opposed to interesting for the value it could bring you later). There's a balance here. Yes, invest in your future. And yes, take some time for "not working on the future" now.