It depends on your goal and how much you want to learn of course.
If you find some materials not fun to learn, then you can remove them if you want. Nothing is wrong with that. I did that a couple of times when finding that my learning process needs an major overhaul.
I use Anki mostly for self-learning and also have a lot of cards, and I sometimes worry if I’ll ever study all of them in my lifetime, so I increase the daily card limit occasionally and study like mad
I recommend lowering the daily card limit or learning some effective strategies to make cards.
I find Anki more boring when I study passively and not engage of what I’m learning and just press the space bar so I can finish my daily workload. If you find youself doing that, I recommend taking rest to think about your learning process and goals.
I’m not the one to advice on effective learning strategies, but I would say that you should try to study actively most of the time by engaging with what you learn and focusing on the process rather than on finishing all your cards, especially if your goal is lifelong learning.
Of course, you should read Twenty rules of formulating knowledge on the SuperMemo site.