set output DAR lags to prores

[Selur]

Okay, input PAR is 8:9 = 1.333.... ~ DAR: 20:15 which in the debut output get's passed on t the encoding call:

"/usr/local/bin/vspipe" "/Volumes/xxxx/encodingTempSynthSkript_2023-05-08@18_00_08_0410.vpy" - -c y4m - "/Applications/Hybrid.app/Contents/MacOS/ffmpeg" -y -noautorotate -nostdin -threads 8 -f yuv4mpegpipe -i - -an -sn -vf zscale=rangein=tv:range=tv -pix_fmt yuv422p10le -strict -1 -vsync 0 -vcodec prores_ks -profile:v 1 -vtag apcs -aspect 20:15 -metadata encoding_tool="Hybrid 2022.03.20.1" -f mov "/Volumes/xxxx/CP_Hi8_703_2023-05-08@18_00_08_0410_03.mov"

Since your input is NTSC you should the correct input PAR is probably: 38800/42651 (assuming it originally was an analog source which wasn't resized).
So, try setting Crop/Resize->Base->Pixel Aspect Ratio (PAR)->Input PAR to 38800:42651 and depending on what you want to do with it later adjust 'Convert output to PAR'.

MPEG-4:  (common for MPEG-4 based content)

DAR	PAL	NTSC
4:3	12/11	10/11
16:9	16/11	40/33

ITU-R 601:  (common for analog content)

DAR	PAL	NTSC
4:3	1150/1053	38800/42651
16:9	4600/3159	155200/127953

Generic:  (common for MPEG-2 based content)

DAR	PAL	NTSC
4:3	16/15	8/9
16:9	64/45	32/27

see: [INFO] About pixel aspect ratios,..

After setting the PARs Adjust 'Picture Resize' and 'Letterbox' and check the 'Vapoursynth Preview' to check what is happening, this way you should be able to achieve what you want.

Cu Selur