IW4x via Onion. Download the updater, make a copy of the MW2 installation folder and put the updater inside the copied folder. Once it runs just launch the game using the iw4x.exe and you're good! Don't forget to also check out their discord, link on the site. I playd the iw4x client but with every version of the mod the menu dount open. I dount know why but mey you faunt a thing you/or I can fix so i Can run the menu. I found a way to make this mod work for the steam version of MW2. Just download the RSE mod, Place it in Call of Duty Modern Warfare 2 folder, press yes on overwrite all files.
If you haven't looked into it, and want what MW1 gave you in MW2. Then IW4x is seriously the way to go. Its super easy to install and the community is surprisingly active.
This mod has a ton of added content and features. Custom FOV, unlocked framerate, support for custom maps, custom mods and much more!
IW4x via Onion
Download the updater, make a copy of the MW2 installation folder and put the updater inside the copied folder. Once it runs just launch the game using the iw4x.exe and you're good!
Don't forget to also check out their discord, link on the site.