TIL I can use Emacs Tramp not only to use sudo on localhost with the Emacs running under unprivilidged user:

C-x C-f /sudo:localhost:/path/to/file RET

or that I can ssh with Emacs:

C-x C-f /ssh:pilosus@raspberrypi:/path/to/file RET

but I also can pipeline ssh session with sudo:

C-x C-f /ssh:pilosus@raspberrypi|sudo:raspberrypi:/path/to/file RET

which is a shortcut for:

C-x C-f /ssh:pilosus@raspberrypi|sudo:root@raspberrypi:/path/to/file RET