Undervolting Nvidia is not possible at the moment on Linux, for overclocking green with envy should work like the other poster said. Be sure to read up on setting Coolbits to unlock overclocking for Nvidia: https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Enabling_overclocking
Make sure your ancient laptop has vulkan support, if it doesn’t you can’t use dxvk or vkd3d and have to use the directx->opengl wrapper in wine (wined3d), performance will not be good with it and you’d probably be better off with windows.