I got everything to work now.
First of all I have just reinstalled windows and forgot to run the command to add vapoursyth to path. It turned out that both filters were actually stuttering BUT I managed to fix vapoursynth not to have any framedrops in 4k by unchecking in filter properties all the 10-bit and 16-bit input formats and now SVP works with it (because of the path) and there is no stuttering/framedrops at all.
https://www.tiktok.com/@hl24a3/video/75 … 6865974550
https://www.tiktok.com/@hl24a3/video/75 … 6118029590