This is a copy of my comment from Reddit.

My Linux distro is EndeavourOS (Arch Linux but installed with graphical installer), I installed pcsx2-git from AUR which currently provides version 1.7.4282.r0.g6d7eceb4f-1, I will give a rundown on what I did to get P3F Community Enhancement Pack on Linux.

1. Get a Windows system (P3F Community Enhancement Pack requires that)

2. Follow P3F Community Enhancement Pack's installation instruction step by step.

3. Boot back to Linux and mount whatever disk partition that has P3F Mods folder.

4. Rename your old PCSX2 config directory if you already played for a while (~/.config/PCSX2 to ~/.config/PCSX2.bak) (In Linux "~" equals to /home/)

5. run pcsx2 once and close it to generate default config folder.

6. Copy everything under P3F Mods/Files to ~/.config/PCSX2.

7. Copy P3F Mods/.PCSX2/inis to ~/.config/PCSX2 and override original inis directory.

8. Open ~/.config/PCSX2/inis/PCSX2.ini with any text editor.

9. remove all occurrences of ..\Files\. (for example, Bios = ..\Files\bios becomes Bios = bios)

10. change Snapshots = ..\Notes\snaps to Snapshots = snaps and "Logs = ..\Logs\logs" to "Logs = logs"

11. save PCSX2.ini and close text editor.

12. open a terminal (a program which lets you do Linux commands)

13. do cd ~/.config/PCSX2

14. do pcsx2-qt -elf elf/SLUS_216.21.ELF -batch -fastboot -nofullscreen -- iso/P3F.iso

15. Does the game run? Did you see "P3F CEP" logo? (I hope it work for you too.)

16. To restore old save, copy memcards folder from ~/.config/PCSX2.bak.

17 To quickly launch p3f, you can put a function under ~/.bashrc

function p3f() {
cd ~/.config/PCSX2
pcsx2-qt -elf elf/SLUS_216.21.ELF -batch -fastboot -nofullscreen -- iso/P3F.iso
}

then you can just type "p3f" to launch p3f.