Time to inquire about this again.

No, there are too many things for that. When can I expect this done? I use a lot of changing post effects and it's kinda hard to make new graphics when you can't see the final result.

What makes this difficult to implement? Doesn't Unity provide good ways to modify the profile?

Please tell me there is progress. 

Yo, that looks sweet. 

Alright, looking forward to it.

Sorry, I was a bit confused that I thought I wrote something wrong. I'm using this. http://staggart.xyz/unity/sc-post-effects/scpe-docs/?section=sc-post-effects

For my own shaders I use Amplify Shaders which auto generates a script for me. It can look like this.// Amplify Shader Editor - Visual Shader Editing Tool
// Copyright (c) Amplify Creations, Lda <info@amplify.pt>
#if UNITY_POST_PROCESSING_STACK_V2
using System;
using UnityEngine;
using UnityEngine.Rendering.PostProcessing;

[Serializable]
[PostProcess( typeof( ColourAdjustPPSRenderer ), PostProcessEvent.AfterStack, "Colour Adjust", true )]
public sealed class ColourAdjustPP : PostProcessEffectSettings
{
[Tooltip("Brightness")]
[Range(-1f, 1)]
public FloatParameter Brightness = new FloatParameter { value = 0f };
[Tooltip("Contrast")]
[Range(-1f, 1)]
public FloatParameter Contrast = new FloatParameter { value = 0f };
[Tooltip("Saturation")]
[Range(-1f, 1)]
public FloatParameter Saturation = new FloatParameter { value = 0f };
[Space(5)]
[Header("Tint")]
[Tooltip("H")]
[Range(0f, 1)]
public FloatParameter H = new FloatParameter { value = 0.5f };
[Tooltip("S")]
[Range(0f, 1)]
public FloatParameter S = new FloatParameter { value = 1f };
[Tooltip("V")]
[Range(0f, 1)]
public FloatParameter V = new FloatParameter { value = 0f };
}

public sealed class ColourAdjustPPSRenderer : PostProcessEffectRenderer<ColourAdjustPP>
{
public override void Render( PostProcessRenderContext context )
{
var sheet = context.propertySheets.Get( Shader.Find( "Colour Adjust" ) );
sheet.properties.SetFloat( "Brightness", settings.Brightness );
sheet.properties.SetFloat( "Contrast", settings.Contrast );
sheet.properties.SetFloat( "Saturation", settings.Saturation );
sheet.properties.SetFloat( "H", settings.H );
sheet.properties.SetFloat( "S", settings.S );
sheet.properties.SetFloat( "V", settings.V );
context.command.BlitFullscreenTriangle( context.source, context.destination, sheet, 0 );
}
}
#endif

Now, I don't expect a custom action for everything, that would be insane and it wouldn't work for my own stuff.
Using Get/Set properties does not work but maybe a custom action that can get/set the shaders variables in the profile?
Maybe something like the Conditional Expression action, there you have to write the variables and logic yourself would work?

I'm wondering how I can modify my PP profile. I've checked out the package on Eco but most of my effects are custom made and I wonder how I can access them.

I'm looking for a way to turn them on/off and change their values.

I actually did a search for ABS and negative but I found nothing. It's really easy to not find what you are looking for unless you type it exactly so I missed it. Thanks.