So I checked your gameplay videos, Toco, and I have some very specific advice for you:
1. Get a new skin. Your current one makes playing way harder than it should be. Get an efficient skin like Nexus or Lithe. (It doesn't have to be exactly one of those, feel free to edit it any way you like, but stuff like the lighting.png and hitbursts should be non-distracting... your current skin makes it impossible to follow the map. Here's what I use for example: custom-skin, pay attention to: followpoint.png, hit300.png, hit300k.png, hit300g.png, lighting.png, reversearrow.png, sliderfollowcircle.png, spinner-clear.png, spinner-osu.png)
2. Don't start playing Hards yet. You're not prepared for it. Ignore the people that told you to retry hards a million times, they probably didn't see your current level. Doing so will not help you learn anything at all right now; Right now you have trouble reading timings of hits on a map - you can't tell where is a 1/4 spacing, a 1/2 spacing or a 1/1 spacing (on timeline). Keep playing normals with HardRock but without other mods until you can get 95% accuracy or higher on every Normal you play every time you play it. Also, focus on playing many different maps instead of re-playing the same one map. This will make your reading improve the fastest.
Once you can get 95%+ accuracy on every normal you play, your reading is good enough to start trying to play Hards. At that point you will be able to follow what's going on and you'll be able to practice them properly and have fun playing them.
Also, DO reduce your mouse DPI like everybody said. Your mouse accuracy will go up instantly if you get a DPI below 1000. 3000 is ridiculous... something in the range of 400-1200 is much easier to play with. If you're having trouble learning to play 800DPI from 3000, do this: set your settings for 800 DPI, but then set the osu modifier to 0.5x, so that you essentially get 400DPI while playing osu. Play like that for 3-4 hours, use NoFail, and finish maps completely, don't retry or anything, try to do the best you can per map and aim for max accuracy regardless of what happens (i.e. keep trying, don't just give up halfway). After you did this for 3-4 hours, switch to 1.0x modifier - and suddenly 800DPI will feel super fast and you'll get natural with it instantly.
Last note: make sure you're playing recent maps (check the map date before downloading), preferably maps made in the last 5-6 months. Older maps will not help you improve as much as newer ones... simply because most of old maps are poorly timed or have other problems.
1. Get a new skin. Your current one makes playing way harder than it should be. Get an efficient skin like Nexus or Lithe. (It doesn't have to be exactly one of those, feel free to edit it any way you like, but stuff like the lighting.png and hitbursts should be non-distracting... your current skin makes it impossible to follow the map. Here's what I use for example: custom-skin, pay attention to: followpoint.png, hit300.png, hit300k.png, hit300g.png, lighting.png, reversearrow.png, sliderfollowcircle.png, spinner-clear.png, spinner-osu.png)
2. Don't start playing Hards yet. You're not prepared for it. Ignore the people that told you to retry hards a million times, they probably didn't see your current level. Doing so will not help you learn anything at all right now; Right now you have trouble reading timings of hits on a map - you can't tell where is a 1/4 spacing, a 1/2 spacing or a 1/1 spacing (on timeline). Keep playing normals with HardRock but without other mods until you can get 95% accuracy or higher on every Normal you play every time you play it. Also, focus on playing many different maps instead of re-playing the same one map. This will make your reading improve the fastest.
Once you can get 95%+ accuracy on every normal you play, your reading is good enough to start trying to play Hards. At that point you will be able to follow what's going on and you'll be able to practice them properly and have fun playing them.
Also, DO reduce your mouse DPI like everybody said. Your mouse accuracy will go up instantly if you get a DPI below 1000. 3000 is ridiculous... something in the range of 400-1200 is much easier to play with. If you're having trouble learning to play 800DPI from 3000, do this: set your settings for 800 DPI, but then set the osu modifier to 0.5x, so that you essentially get 400DPI while playing osu. Play like that for 3-4 hours, use NoFail, and finish maps completely, don't retry or anything, try to do the best you can per map and aim for max accuracy regardless of what happens (i.e. keep trying, don't just give up halfway). After you did this for 3-4 hours, switch to 1.0x modifier - and suddenly 800DPI will feel super fast and you'll get natural with it instantly.
Last note: make sure you're playing recent maps (check the map date before downloading), preferably maps made in the last 5-6 months. Older maps will not help you improve as much as newer ones... simply because most of old maps are poorly timed or have other problems.