I run Ubuntu with BTRFS, no issue.

Games and game/steam environment variables is very high software chain. Based on what your are reporting.

Ie Phoronix: Windows 11 vs. Ubuntu Linux Performance On The AMD Ryzen AI Max PRO 390 “Strix Halo”

On a geometric mean basis, Ubuntu 25.04 was around 13% faster than the OEM install of Microsoft Windows 11 Pro that shipped on the HP ZBook Ultra G1a laptop.

Or

Tom’s hardware: Cyberpunk Phantom Liberty Runs 31% Faster on AMD GPUs in Linux Compared to Windows 11

You need to look at something low level. There is something unique wrong with laptop + kernel combination. Most search for why a game performance badly will not help you.

There has been many reported issues of unique issues for laptops that have taken a lot of work to fix like Linux 7.1-rc4 Seeing The Latest Laptop Quirks

If you are going to use Ilm I recommend using Claude Opus or equivalent. And Run in Claude Code and start with something like “I am running the following hardware:… I am seeing performance regression when running under Linux vs windows. Start with making me scripts to test and document low level performance for both windows and Linux”

I found that llms can be useful in troubleshooting.

Maybe start with comparing hardware sensor stats GPU/CPU temp/frequency/fan etc.

I think is useful to use a bleeding edge OS since what you are talking about, is a combination of kernel/drivers, user space tools and software.

Start with something low level maybe clpeak or as part of Phoronix Test Suite. A game is a complex software that touches many parts of a system, especially for laptops where some resources are shared.

You guys still run Windows?!