Your pc isnt bad, it should run well but it depends, if you add lots of NPC's, it will run bad no matter how good your PC is and also, have you changed graphics settings? I think it was the mirror one that kills the performance, go to settings and set the game on ultra to reset all de video settings, if it doesn't work, try high and restart.

mess with the settings .....

The game though old, tends lag a lot when it comes to how it renders certain things; skid marks all the way to reflections. easiest way to fix it is to manually tune and tone some of the settings down. And also maybe try rendering it in 1080p too. 1440p can be alright but, its not exactly 60fps ....

my specs are:
thread-Ripper 2070wx
dual rtx 3090's
128gb ram.

I still have to tune it ...