CS always missed the point of spray.
Originally there were no spray patterns, you just pulled down varying amounts on all weapons and prayed that you would hit. This was obviously shit, so they added spray patterns to increase the skill ceiling of the game (you need to memorise spray patterns and have understanding of how to resume them or burst etc), and reduce the RNG. Obviously it is incredibly unrealistic, and relies completely on muscle memory.
For anyone wonder, the CORRECT way to do spray is to have the player shoot -> recoil moves the gun some amount (even partially randomly), and then the player can manually adjust their crosshair to keep it on target, and shoot the next bullet. When firing full auto the player has a fraction of a second to constantly adjust their aim. This is a good mechanic, it is 100% mechanics and 0% memory.
For P90 DO NOT HOLD TRIGGER FOR TOO LONG. The first like 10-20 are just down and slightly left, that's damn easy to remember. You can even burst the first 5 for minimal movement. Shoot and reset, or get really close and bhop strafe and just spray right at them. The P90 has very little spray so you can hit like crazy even by only pulling down.
CS has a shit ton of mechanics that you "just have to know". Honestly it's not a good design for a casual nor a competitive game.