SUMMARY

Sorry, but I don't know if must be kwin or plasmashell... 

When I trigger the windows presentation, or when I  am triggering the window switch with alt+tab there a lot of in journal:

kwin_scene_opengl: 0x1: GL_INVALID_OPERATION in glDrawBuffers(unsupported buffer GL_BACK_LEFT

Lagginess get worse when some other effect is activated while the window switch is active, things like move the mouse with the "shake-to-find" effect around the thumbnails or activate the thumbnail hovering the taskbar thumbnail could hang for a second everything. While this happens, a lot of:
kwin_wayland[1626]: kwin_scene_opengl: 0x1: GL_INVALID_OPERATION in glDrawBuffers(unsupported buffer GL_BACK_LEFT)
(and kwin_wayland[1626]: kwin_scene_opengl: 0x1: GL_INVALID_VALUE in glScissor but this is reported in other issue).

and occasionaly it may cause 

plasmashell[1854]: kf.windowsystem.wayland: Failed to recreate shadow for ToolTipDialog(0x6303f3827470)
plasmashell[1854]: qt.qpa.wayland: eglSwapBuffers failed with 0x300d, surface: 0x0

The gldrawbuffers message also happens when working with two screen outputs, moving the mouse cursor across screens while alt+tab is pressed presents some lagginess.

I am working with two two output screens like these: 

Output: 1 eDP-1
        enabled
        connected
        priority 1
        Panel
        Modes:  0:2560x1600@60*!  1:1600x1200@60  2:1280x1024@60  3:1024x768@60  4:2560x1600@60  5:1920x1200@60  6:1280x800@60  7:2560x1440@60  8:1920x1080@60  9:1600x900@60  10:1368x768@60  11:1280x720@60 
        Geometry: 0,0 1280x800
        Scale: 2
        Rotation: 1
        Overscan: 0
        Vrr: Automatic
        RgbRange: Automatic
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile:  TPLCD_41A3_SDR.icc
        Color profile source: ICC
        Brightness control: supported, set to 100%
Output: 2 DP-2
        enabled
        connected
        priority 2
        DisplayPort
        Modes:  0:3840x2160@60*!  1:3840x2160@30  2:3840x2160@30  3:3840x2160@30  4:3840x2160@25  5:3840x2160@24  6:3840x2160@24  7:2560x1440@60  8:1920x1080@60  9:1920x1080@60  10:1920x1080@60  11:1920x1080@30  12:1920x1080@30  13:1600x900@60  14:1280x1024@60  15:1280x800@60  16:1152x864@60  17:1280x720@60  18:1280x720@60  19:1280x720@60  20:1024x768@60  21:800x600@60  22:720x480@60  23:720x480@60  24:640x480@60  25:640x480@60  26:640x480@60 
        Geometry: 1280,0 1920x1080
        Scale: 2
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: Automatic
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile:  27ud59-b-rtings.icc
        Color profile source: ICC
        Brightness control: supported, set to 100%



SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.1.90
KDE Frameworks Version: 6.6.0
Qt Version: 6.8.0
Kernel Version: 6.10.10-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 15.4 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics
Manufacturer: LENOVO
Product Name: 20W8000ESP
System Version: ThinkPad X13 Yoga Gen 2