Ive been showering lil quick and actually thought about that "imrpoving" process in Osu.
Ive just compared your current skill with a friend of mine who has a play count of a bit more of 24k as well, you are both having pretty much the same pp, so you seem to be on track.
If we keep in mind that Osu! is more of a mind sport than a physical one (except that stamina thing) it makes sense to play more frequent BUT not as long at a time. If you overheat your CPU because it ran for too long, it does more harm than good.
Saying if you play 1 hour and take a break of 3 hours and then play another 1 hour will improve your more than you playing 3 hours straight in a row.
Cause when ever you improve, your neuroplastic brain changes, it has to rewire in order to improve things such as your muscle memory or your reaction, your reading ability etc. but it takes time for your brain so you have to give your brain a break.
What I mean by that is that I most of the time experience a massive skill boost when I play like 2 hours maps where I only get 85-90% and then don't play at all the next day, then I improve massively the next day after the break day, meaning on the break day, my brain did rewire in order to make that improvement happen, my brain wouldn't be able to rewire tho if I overuse to neuro pathways which have to become stronger.
If you take a weekend doing research about basic neuro-science, you'll get the hang of it.
Another easy way to improve is to take maps you are quite good at and then creating a custom practice map for yourself, where you increase the cs to 5 instead of 4 and the AR to 9.4 instead of 9.0 so you give yourself a challenge since you are used to cs4 and AR9...unless you play hr.
I just think you shouldn't play AR10 in order to be better in AR9, only push it a lil bit, like 9.2-9.5 and create your set of improvement maps.
And then the same thing again, let's say you gonna play the last hour of the day, that's the time where u play your custom maps only, so your brain has a trigger to rewire and then you give yourself a break for a day...
I hope this is a better explanation on "HOW TO BECOME BETTER" because if you only play more, u won't improve as fast as you could...but people don't seem to criticise their "PLAY MORE"hype