EDIT: Seems that adding LD_PRELOAD="" %COMMAND% on steam's launch options fixed my problem. Thanks a lot, everyone :)
I don't know why this happens, I tried playing on windowed, borderless windowed and fullscreen and this bug always happens.
Here's my fastfetch info:
OS: Arch Linux x86_64
Host: Nitro AN517-54 (V1.20)
Kernel: Linux 6.14.5-arch1-1
Uptime: 2 hours, 18 mins
Packages: 1271 (pacman), 20 (flatpak)
Shell: zsh 5.9
Display (eDP-1): 1920x1080 @ 60 Hz in 17" [Built-in]
DE: KDE Plasma 6.3.5
WM: KWin (Wayland)
WM Theme: Breeze
Theme: Breeze (Dark) [Qt], Breeze-Dark [GTK2], Breeze [GTK3]
Icons: breeze-dark [Qt], breeze-dark [GTK2/3/4]
Font: Noto Sans (10pt) [Qt], Noto Sans (10pt) [GTK2/3/4]
Cursor: breeze (24px)
Terminal: konsole 25.4.0
CPU: 11th Gen Intel(R) Core(TM) i5-11400H (12) @ 4.50 GHz
GPU 1: NVIDIA GeForce RTX 3050 Mobile [Discrete]
GPU 2: Intel UHD Graphics @ 1.45 GHz [Integrated]
Memory: 4.34 GiB / 15.40 GiB (28%)
Swap: 0 B / 16.94 GiB (0%)
Disk (/): 255.23 GiB / 450.71 GiB (57%) - ext4
Disk (/mnt/ssd): 298.43 GiB / 439.04 GiB (68%) - ext4
Battery (AP18E7M): 33% (1 hour, 2 mins remaining) [Discharging]
Locale: en_US.UTF-8
Are you monitoring component temperatures?
No. That's a good idea, I'll start doing it.
Yeah the fact that it takes a while to start happening leads me to believe you may be thermal throttling somewhere.