Hello all again.
I recently installed Debian-12. Your advises calmed me but will be used it's tomorrow so as now eyes shutting down.
Good morning!
I began since top of your advices i.e.
https://wiki.debian.org/NewInBuster#Changes and reading: "The su command in buster is provided by the util-linux source package, instead of the shadow source package, and no longer alters the PATH variable by default. This means that after doing su, your PATH may not contain directories like /sbin, and many system administration commands will fail. There are several workarounds:
Use su - instead; this launches a login shell, which forces PATH to be changed, but also changes everything else including the working directory."
It was tried and at once into point!,
further I didn't read as fear to tangle.
All to luck!
--fuf