No, you're not bad. It's important to remember that rank, pp, and the stars rating system for mania are all not that accurate. You shouldn't focus on others' improvement and compare it to your own. The best thing you can do is compare yourself with yourself. When trying to improve yourself, stick to Local Ranking when checking the leaderboard and have your goal always be to beat your high score on a map. Try not to mind the difficulty rating for songs, it pains me to admit there are still 2* maps I only have a B on. When playing this game, you should have fun and be proud of your accomplishments, no matter how minor they may seem. Even beating your high score by 1% is something you should be proud of.
Spamming on maps isn't necessarily bad, I only see it becoming bad when you get in the habit of spamming on hard sections of maps. I think it's important to expose yourself to maps beyond your level, but you should be working on making B's into A's and A's into S's more.
I agree with everything [TAS] said. I've met many people that believe that rank, play time, and level are all measurements of skill, potential, talent, etc. That's not true at all. What really matters in this game is wellroundedness. I think this is best shown in tournaments (I'm not that experienced with tournaments, so I might be wrong about this lol, feel free to contradict me on this older players). My first tournament, I got my ass kicked in the qualifiers because I didn't like playing LN maps, didn't practice them, and did terribly on them. It taught me a lesson and I've done a lot of practicing with LN since then.
I guess what I'm trying to say is relying on numbers like your rank, your level, your playtime, etc will hinder your improvement. People that play pp maps to boost their rank become the most disappointed when they stop gaining rank when they run out of pp maps. Players will avoid using HR because it makes their scores unranked and they don't gain rank. Players will avoid low-rated maps, even though they struggle with the patterns in them, because their star count is low. People will never even try going beyond 4k to the higher keycounts because they can gain rank faster focusing only on 4k. Try to remember that as long as you practice, you're becoming better, even if it doesn't seem like you are.