Looks to me like nouveau and your 10de:128b GPU should not be issues. My GK208B/GT 720/10de:1288 works just fine, though I use neither SDDM nor Plasma6 nor Wayland:
# inxi -GSaz --vs --za --hostname
inxi 3.3.36-00 (2024-09-04)
System:
Host: hp945 Kernel: 6.11.2-1-default arch: x86_64 bits: 64 compiler: gcc
v: 14.2.0 clocksource: tsc avail: hpet,acpi_pm
parameters: root=LABEL= ipv6.disable=1 net.ifnames=0 noresume
nomce consoleblank=0 mitigations=off
Desktop: KDE Plasma v: 5.27.10 tk: Qt v: 5.15.12 info: frameworks
v: 5.115.0 wm: kwin_x11 vt: 7 dm: 1: KDM 2: XDM Distro: openSUSE Tumbleweed
20241007
Graphics:
Device-1: NVIDIA GK208B [GeForce GT 720] vendor: Micro-Star MSI
driver: nouveau v: kernel non-free: series: 470.xx+
status: legacy-active (EOL~2024-09-xx) arch: Kepler-2 code: GKxxx
process: TSMC 28nm built: 2012-2018 pcie: gen: 1 speed: 2.5 GT/s lanes: 8
ports: active: DVI-D-1,HDMI-A-1 empty: VGA-1 bus-ID: 01:00.0
chip-ID: 10de:1288 class-ID: 0300 temp: 52.0 C
Display: x11 server: X.Org v: 21.1.12 compositor: kwin_x11 driver: X:
loaded: modesetting dri: nouveau gpu: nouveau display-ID: :0 screens: 1
Screen-1: 0 s-res: 1920x2250 s-dpi: 120 s-size: 406x476mm (15.98x18.74")
s-diag: 626mm (24.63")
Monitor-1: DVI-D-1 pos: top model: Dell P2213 serial: built: 2013
res: 1680x1050 hz: 60 dpi: 90 gamma: 1.2 size: 473x296mm (18.62x11.65")
diag: 558mm (22") ratio: 16:10 modes: max: 1680x1050 min: 720x400
Monitor-2: HDMI-A-1 mapped: HDMI-1 pos: primary,bottom model: NEC EA243WM
serial: built: 2011 res: 1920x1200 hz: 60 dpi: 94 gamma: 1.2
size: 519x324mm (20.43x12.76") diag: 612mm (24.1") ratio: 16:10 modes:
max: 1920x1200 min: 640x480
API: EGL v: 1.5 hw: drv: nvidia nouveau platforms: device: 0 drv: nouveau
device: 1 drv: swrast gbm: drv: nouveau surfaceless: drv: nouveau x11:
drv: nouveau inactive: wayland
API: OpenGL v: 4.5 compat-v: 4.3 vendor: mesa v: 24.1.7 glx-v: 1.4
direct-render: yes renderer: NV106 device-ID: 10de:1288 memory: 983.4 MiB
unified: no
API: Vulkan v: 1.3.290 layers: 3 device: 0 type: cpu name: llvmpipe (LLVM
18.1.8 128 bits) driver: N/A device-ID: 10005:0000 surfaces: xcb,xlib
# zypper --no-refresh se -s -i 5-sess sion-x11 sddm kdm Mesa veau mwar | egrep -v 'debug|devel|srcp|openSUSE-20' | egrep 'x86|noarch'| sort -f
i | Mesa | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-dri | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-gallium | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-libEGL1 | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-libGL1 | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-libglapi0 | package | 24.1.7-391.1 | x86_64 | OSS
i | Mesa-vulkan-device-select | package | 24.1.7-391.1 | x86_64 | OSS
i+ | alsa-firmware | package | 1.2.4-4.6 | noarch | OSS
i+ | kdebase3-kdm | package | 3.5.10.1-382.1 | x86_64 | KDE3
i+ | kernel-firmware-intel | package | 20241001-1.1 | noarch | OSS
i+ | kernel-firmware-nvidia | package | 20241001-1.1 | noarch | OSS
i+ | libOSMesa8 | package | 24.1.7-391.1 | x86_64 | OSS
i+ | libvulkan_nouveau | package | 24.1.7-391.1 | x86_64 | OSS
i+ | Mesa-demo-egl | package | 9.0.0-3.3 | x86_64 | OSS
i+ | Mesa-demo-es | package | 9.0.0-3.3 | x86_64 | OSS
i+ | Mesa-demo-x | package | 9.0.0-3.3 | x86_64 | OSS
i+ | Mesa-dri-nouveau | package | 24.1.7-391.1 | x86_64 | OSS
i+ | Mesa-libd3d | package | 24.1.7-391.1 | x86_64 | OSS
i+ | Mesa-libOpenCL | package | 24.1.7-391.1 | x86_64 | OSS
i+ | Mesa-libva | package | 24.1.7-391.1 | x86_64 | OSS
i+ | Mesa-vulkan-overlay | package | 24.1.7-391.1 | x86_64 | OSS
i+ | sof-firmware | package | 2024.09-1.1 | noarch | OSS
il | plasma5-session | package | 5.27.10-3.2 | noarch | (System Packages)
#