Ok, that’s better. It’s a higher-specd model with 2 nvidia cards; I guess you switch via a MacOS utility similar to KDE Plasma not starting after installing Nvidia non-free driver on 2012 MacBook Pro - #15 by 6x12 . However, in 2022 they are both lame but at least they share both open source and proprietary driver.
The advantage of the GeForce 9600M GT would be that the dedicated 256MB video ram would give you your full 4GB ram whereas your GeForce 9400M pinches it’s ram from the 4GB system ram. Since we’re both on 3.58 GiB ram, we both have GeForce 9400M running and are therefore on (almost) identical machines.
To make this a usable machine I’d open it, remove the 14 years old spinner drive (which most likely is the reason for your ‘things are getting worse’ issues) and either clone it to an ssd or put a blank ssd in and reinstall xfce. While you have it open you could swap the ram to 2x4GB (27€, G.Skill SO-DIMM 8 GB DDR3-1066 Kit, Arbeitsspeicher F3-8500CL7D-8GBSQ, Lite Retail ).
Swapping the drive will take 15- 20 min, it’s super easy (How to Upgrade a 15-inch MacBook Pro (Mid 2009) Hard Drive/SSD - YouTube). This is by far the most important step to make the machine usable in 2022, just checked, mine boots in 20 sec to desktop, with my old spinner it’s more like 2min.
Second probable reason for the wakeup issues is the nouveau driver. While it usually works ok it’s a little more erratic and needs all eye candy turned down. In Control Centre >> Windows Manager Tweaks >> Compositor set transparencies to ‘opaque’ and remove as many ticks as possible. Also install 5.4LTS and 5.10LTS and try both, at times a kernel update will cause issues and you’ll have to try the other kernel or avoid suspend altogether.
If you got this far you can install the nvidia-340xx-dkms driver, Instructions are here in the forum, but I seriously wouldn’t try this unless you got a usable machine with the steps above.