Here is interim version
FRIM 1.32 which will solve your problem.
Please test it and confirm.
(I will publish it later as official release.)
Code:
set ISTREAM=input.h265
set OSTREAM=ouput.h265
set PSTREAM=\\.\pipe\yuvpipe
start /min .\FRIMDecode64 -i:h265 "%ISTREAM%" -sw -o %PSTREAM% -yuv420p10le
ffmpeg -hide_banner -f rawvideo -s 3840x2160 -r 23.976 -pix_fmt yuv420p10le -i %PSTREAM% -vcodec hevc "%OSTREAM%"
For this RawSourcePlus() it should work as well.