If you really want to play better in Osu! I suggest you get ready putting endless hours of practice for weeks, months etc... I am just joking
My first experience playing Osu! was terrible, I had no idea how to play it, I didn't even use the keyboard..... The only thing that used was a mouse and the buttons of the mouse.
I would be playing 1 and 2-star maps and there wouldn't be any problem with a mouse. However, later on, the streams got introduced to me and doing them with a mouse was insane. So, I researched and saw Pro players such as Cookiezi (he is pretty much the famous guy in Osu!) and saw him using a keyboard, it doesn't matter what switches you have (please don't use green-switch, its trash). Basically, I learned to use the two keys Z and X and got better by just playing a lot.
Streams: when many circles are together that makes a pattern, you can look at it as a slide and follow the circles to hit them right
Is this not fascinating? I got better by just playing more
How hard can it actually be?
Of course, you will be trash at first, but by playing more you will improve your speed, aim, and consistency. The skill will come to you in time, don't play too much nor don't repeat the same map 100 times in a day, you will not improve your overall skill, However, you will create a muscle memory that will be useless when it comes to other maps.
Anyway, I hope it will help. If it still didn't help and that is probably 100% likely to be true, go watch some youtube videos about Osu! on how to improve, there will be people giving good advice and bad advice, just watch few videos to see what similar things they are saying and pick on that.