It is possible that the issue is not related to your graphics card, but rather to the optimization of the game itself. Diablo II: Resurrected is a remastered version of a game that was originally released in 2000, so it is possible that the game engine is not optimized for modern hardware.
There are a few things you can try to improve your FPS in D2R:
Update your graphics drivers to the latest version.
Lower some of the graphics settings in the game, such as shadow quality and particle effects.
Disable V-sync in the game settings.
Close any other programs that may be running in the background while you are playing the game.
Check if there are any known issues with D2R and your specific graphics card model.