This erroneous line in .bashrc caused the booting issue (I’ve reinstalled on another drive, the same symptoms after restoring specific files and directories to /home/user/):
alias edit-aliases='nano ~/.bash_aliases' && source ~/.bashrc
corrected:
alias edit-aliases='nano ~/.bash_aliases && source ~/.bashrc'
Marking as a solution, even though the other answers were more informative in general.
I have to learn analyzing system logs, the problem could likely have been easily resolved soon after the first failed boot…