The “qwerty” keyboard arrangement stems from mechanical typewriters. The typewriter was invented in the year 1860 and it became widely famous after that. The tremendous use of typewriter led to increasing the speed of typing. The old technology was not capable of typing so fast. At first, keys were actually arranged alphabetically but the original typewriters were mechanically slower. So for a quick typist, it created a huge problem. So all keys were aligned in a different pattern to slow down the typing speed of the typist.
If you see your keyboard the letter ‘a’ , ‘s’ , ‘e’ are on the left side. These letters are used the most. So they were given on the left side as your left hand will function slower than your right hand. Of course, lefthander will be a benefit but lefthanders are less in number. Also, all the vowels which are used most while typing are kept far apart. If you see above your space key ‘n’ is kept first and then ‘m’. This is to confuse typist. All these arrangements were only made to slow down the typing speed.
The “qwerty” Keyboard came after typewriter and made typewriter obsolete. But the pattern was never changed after that.
But today the pattern of the keyboard does not matter. I have seen people typing even faster than they can read or write. Our brain has actually accustomed this pattern.