FIRST
I am not a modder for this game.
I am not a developer for this game.
I am not a developer for the save editor.
I barely know my way around the tool.
I have no knowledge of the consequences or instability that might occur from doing this.
I have no idea if this can harm even backup saves or other saves on the profile.

DO NOT do this if you're invested in a playthrough and would be upset if that run is completely borked.

I am also not a content creator in any meaningful way, so the video linked will be absolute horrid quality.

With that out of the way, here's a quick little explanation of how I did this. Video will show the process and results.

Step one: Save Editor
- I used NovFR's DoS-2-Savegame-Editor ( DL page: https://github.com/NovFR/DoS-2-Savegame-Editor/releases/tag/1.1.0.6 )
- Scroll down to the zip, unpack anywhere (I put it in my Dos2 steam folder)
- Run it to make sure it works and can open a save.
- Close it.

Step two: Multiple saves!
- Open the Dos2, load the campaign you want Pet Power (PP) removed.
- SAVE THE GAME TWICE: one save title like.. "do not edit" and the other one "remove PP" or something easy.

Step three: Use the save editor.
- Your gunna open the editor, open the save you're removing PP from.
- At the top we'll navigate through the "Advanced > Show metadatas' tree"
See video for a walkthrough on what to expand and where to go. Depending on the mods and giftbags you have enabled, you may have to search more or less.

When you open Dos2 again MAKE SURE YOU HAVE "Helaene - Buff All Summons (DE)" enabled!

Hopefully it works like I've had success with. I have noticed if I enable Pet Power AFTER Helaene's mod is enabled, it seems to be able to buff the summons added by mods, but I cannot say if that is a permanent thing, and if you disable Helaene's mod on that save you'll have to remove Pet Power again in order to re-enable the mod properly.

Ultimately, again, I am not a modder, developer, or content creator. This is an absolute barebones effort to get a solution out there that might or might not work. Questions are fine, but understand I have no freakin' idea what I am doing. I just clicked buttons that sound like they do what I want them to do.

Good luck, Godwoken, you might need it...

VIDEO:
https://www.youtube.com/watch?v=b5FyCRHM210