There are a lot of mods that allow you to do exactly that.

My favorite that does exactly as you mention is KOs (Kerbal OS). It's basically a programmers interface for it, allowing for really precise control.

A YouTuber, Scott Manley, has a pretty good (albeit old) video on the topic.

https://www.youtube.com/watch?v=FPDPzsnlHOI

Vanilla KSP makes you do everything by hand. That's part of the fun, IMO, but after you get good at landing and docking it can turn into a chore when you need to fly multiple missions to e.g. build a colony. However, there are many mods that will let you automate some or all parts of the gameplay.

Two particular mods worth mentioning are MechJeb, the autopilot for everything, and kOS, which lets you code up your own guidance system.

Other commenters have mentioned both Kerbal OS or MechJeb. Kerbal OS will let you geek out on programming your own routines while MechJeb will just handle the "boring stuff" for you like maintaining a particular vector while you do the "cool stuff" like navigation and mission planning. Some say these mods are like cheating, but once you can get a ship into orbit with your eyes closed, repeating that every time isn't really the fun part anymore.

try mechjeb.

MechJeb doesn't do proper roll, pitch, gravity turn launches either. It does a pre-programmed ascent profile.

In reality all the control of a space launch takes place in the first seconds when the vehicle is subsonic. After that it's just pointing to the direction of travel because any angle of attack in the atmosphere would cause excess aerodynamic stress.

That's why launch controllers say "nominal" that often. There's nothing that can be done, just hoping that the vehicle stays within the planned bounds.

All the accumulated errors from atmospheric conditions and other randomness are corrected by the second stage burn once outside the atmosphere.