Why don't I get the correct number of lines from .txt and also random number does not change - batch-file

Question

two things I don't understand what I can do more.
%%C instead of showing me that in output-mp3.txt (%%B) I have one single line -> the output is 124000 lines. If I make the for /f %%C alone in another .bat is showing me the corect number of lines.
I need if %%C == 1 to get !exportname! (%%~nB) which is the name of the song and if is not equal with 1 to be generated a random name. My conditional command doesn't work also %RANDOM% show all the time the same number when is looped.
If someone have a more professional and optimized approach of what I need I will very gladly to hear any directions.
#echo off
Setlocal EnableDelayedExpansion
for /F "delims=" %%A in (mp3list-1.txt) DO (
for /F "tokens=2 delims='" %%B in (%%A) DO (
for /f %%C in ('Find /V /C "" ^< %%B') do (
echo %%A
echo %%B
echo %%~nB
echo %%C
Echo Notepad file has %%C lines and the name of the song is %%~nB
if "%%C"=="1" (
set /p exportname=%%~nB
Echo Name of the song
) else (
set /p exportname=!RANDOM!
Echo Random number
)
Echo !exportname!
)
)
)
mp3list-1.txt contain
F:\.....\Videos-1\output-mp3.txt
output-mp3.txt in this case %%B contain
file 'F:\....\Canal-1\Videos-1\name of the song.mp3'
LATER EDIT:
I tried like this also with the third FOR, but same not showing me that I have 1 single line .. batch tell me I have 50k lines, witch is no true... also changed make some other changes.. no luck ..
#echo off
Setlocal EnableDelayedExpansion
for /F "UseBackQ delims=" %%A in ("mp3list-1.txt") DO (
for /F "UseBackQ tokens=2 delims='" %%B in ("%%A") DO (
set "cmd=findstr /R /N "^^" "%%B" | find /C ":""
for /f %%C in ('!cmd!') DO (
echo %%A
echo %%B
echo %%~nB
echo %%C
Echo Notepad file has %%C lines and the name of the song is %%~nB
if "%%C"=="1" (
set /p exportname=%%~nB
Echo Name of the song
) else (
set /p exportname=!RANDOM!
Echo Random number
)
Echo !exportname!
)
)
)

Answer 1

Because your script and comments/questions do not match I have made some guesses / assumptions.
This is what your script does:
%%A is a line from file 'mp3list-1.txt'
%%B is the full path and filename extracted from %%a, this is an mp3 file
%%C is the number of lines in the mp3 file! (this is a binary file not text).
Your comments mention a file named 'output-mp3.txt'.
Just for clarity I have added the file output-mp3.txt to keep the changes close to your code.
But the output-mp3.txt is not needed.
Also the check for number of lines is not needed because this file will have just 1 line (%%B).
Because this mystery file "output-mp3.txt" is neither created, nor used in your code this is a bit of a guessing game.
#echo off
Setlocal EnableDelayedExpansion
for /F "delims=" %%A in (mp3list-1.txt) DO (
for /F "tokens=2 delims='" %%B in (%%A) DO (
> "output-mp3.txt" echo %%B
rem type "output-mp3.txt"
rem for /f %%C in ('Find /V /C "" ^< %%B') do (
for /f %%C in ('Find /V /C "" ^< "output-mp3.txt"') do (
echo %%A
echo %%B
echo %%~nB
echo %%C
Echo Notepad file has %%C lines and the name of the song is %%~nB **
if "%%C"=="1" (
set /p exportname=%%~nB
Echo Name of the song
) else (
set /p exportname=!RANDOM!
Echo Random number
)
Echo !exportname!
)
)
)