Perhaps you could try learning a new language. It could be an interesting activity that would provide multiple benefits.
Anything that interests you, such as your favorite city or place you’d like to visit. A new language or some tactics on your favorite games/shows/etc
Learn and study the things you like and passionate about.. This will make you satisfied at the same time learning something new... As well as information is limited to infinity no matter how much you learn there’s still more
There is always something to learn and study, if you have acquired all there is to know about your field, you can always read and learn something new and unrelated, or touch up on your basics. Studies show that with you forget things you learned years ago, never hurts to revisit what you already know.
You’re learning and studying until the day you die. If you think differently to that, then you’ve learned nothing. Reading books , journals, papers and other such works, have been compiled for you to learn and glean something/anything for your brain to think about and maybe use in your conversation with others. You are always learning and studying. Don’t forget it and don’t fight it. Pick up any book and get in stuck in. You may find a subject which will send you in a new direction, fill you with enthusiasm which you can pass on to others. Fantastic!
I find doing learning a new language gives you something to constantly focus on studying and bettering yourself in, while giving you a feeling of achievement. Duolingo is a free app that has a lot of different language options. Maybe try that out for a week?
I would highly recommend psychology books focusing upon developing long-term psychological health! This is in contrast to self-development books which often go through fads and trends, and may or may not be backed by scientific research and the work of counselors and clinicians. Specifically, books on cognitive behavior therapy will be beneficial for everyone that actively applies it to their thinking and life.
Languages if you like to travel, new kind of sports and another life achieves, books to learn better about yourself, popular psychology)
Even if there does not seem like there is anything you can learn or study, you might still be able to hone the skills you have acquired. Personally, I think that we are often downplaying the role that reading for pleasure has. It keeps us imaginatively involved, so long as we read actively. If you really do not have anything in your agenda, then why not enjoy a nice read? And if you read for pleasure don’t just read passively, try to get involved in the text, try to discover possible routes the narrative or argument might take and consider if the claims made are really sound. Other than that you can also increase your proficiency in your reading skills by trying to read a text quicker or focus on more words of the line you are in one glance to increase the amount of words you are able to comprehend when reading. This way, once you have more things to read and learn you might be even quicker in reading and writing down notes. But after all, there is nothing wrong with just reading for pleasure once in a while 😊
I do believe reading to learn can be enjoyable. You should enjoy learning, like with reading Stephen Hawking or learning to read music or a nonfiction book about popular culture. Learning should be enjoyable.