Greetings Ikumi,
1. No helloworld.pdf has been generated after the procedure.
2. C-x C-e brings up:
(start-process "dummy" (current-buffer) TeX-shell TeX-shell-command-option "ls") Desktop '#*message*-20220824-044008#'
Documents Music
Downloads newest.tex
getorg.aux News
getorg.log new.tex
'#getorg.org#' new.tex~
getorg.out Pictures
getorg.pdf Public
getorg.synctex.gz _region_.tex
getorg.tex sent
getorg.tex~ Templates
getorg.toc testat.aux
'#helloworld.tex#' testat.log
helloworld.tex testat.pdf
hellworld.tex testat.tex
mail test.aux
'#*message*-20220730-045537#' test.log
'#*message*-20220730-054520#' test.pdf~
'#*message*-20220730-054836#' '#test.tex#'
'#*message*-20220730-055337#' test.tex
'#*message*-20220730-060511#' test.tex~
'#*message*-20220730-063003#' '#texnochmaltest.tex#'
'*message*-20220730-063003' texnochmaltest.tex
'*message*-20220801-160735' texnochmaltest.tex~
'#*message*-20220824-032856#' texput.log
'#*message*-20220824-034534#' Videos
So no helloworld.pdf, the corresponding pdfs of the other tex-files have been sucessfully generated via pdflatex.exe in the wsl-debian console; apologies for the mess at home, btw. (Maria Kondo comes to mind ;-) )
3. This time C-x C-e was less verbose and just brought up this in mini-buffer: #<process dummy>
Hopefully, I followed your instructions correctly.
(4.) Thank you for the valuable hint regarding other binaries; I will definitely have to adapt those as well, as instructed by you.
Best regards and thank you very much again for your kind and patient assistance,
Pete