Does the number of problems solved matter or does quality of practice matter more?

Yes, and it's more common than people let on. Most learners go through extended plateaus, especially around medium-difficulty problems and topics like dynamic programming and graphs. The people around you who seem to be progressing smoothly are either not telling you about their stuck periods or are further along a journey that looked exactly like yours earlier. Months of struggle followed by a period where things start clicking is a very typical DSA learning arc.

Look at what you're actually doing during your study sessions. If you're spending most of your time watching solutions rather than attempting problems, that's an approach problem. If you always look for hints within the first few minutes, that's an approach problem. If you can solve problems right after studying a topic but forget them a week later, that's an approach problem. If you're genuinely attempting problems, struggling through them, revisiting old ones, and mixing topics, but progress still feels slow, that's just the normal difficulty of DSA and you need to stay patient.

Because it requires a different way of thinking about problems. Most of DSA is about choosing the right data structure or traversal strategy. Dynamic programming asks you to think in terms of states, subproblems, and transitions, which is a mental model most people haven't built before. The difficulty isn't just the concept, it's the shift in how you approach problems entirely. DP takes longer to click than almost any other topic, and hitting a wall there is one of the most universal DSA experiences there is.