Runs on 15-25 fps in native resolution (with 30 fps lock and disable 3d render cheats on) on some area, is there any way to improve performance other than upgrade my pc?
Most likely not, since the GPU seems to be quite old. There is some settings for performance in Emulation → Graphics → Enhancements/Advanced that you could try tweaking to see if it runs any better.
You have most likely hit your limit unfortunately. You are at a disadvantage being on a laptop which has less performance than a desktop (of the same hardware generation).
For example, your i5-4210U and GeForce 820M are from 2014, a decent gaming PC from 2014 might have i5-4590 with a GTX 770, those probably are still fine today for Citra.