Around 3 and a half years ago I bought a Lenovo Legion without an operating system. I do not remember if exactly from beginning but at least shortly after buying it EndeavourOS "sticked" :-) and remain the running OS on the machine.
Running some updates and rebooting brought me to a black screen with a blinking cursor. I had this in the past when the pacman cache was not cleared and the OS could not boot due to the lack of space. Assuming the same prepared for the chroot only to find out that this was not the cause... here enters "troubleshooting mode". As this post remained in draft for more than 2 months some of the details blurred out. What can I say is that finally I have managed to find the culprit, but did not managed to troubleshoot the system and installed anew. Nevertheless I have learned a few important things that enlarged my "Linux-Know-How" and I am very happy. I am also confident that the system was "salvageable" but the efforts were bigger than setting the system clean. Most probably it had to do with how the Nvidia drivers were "talking" to the kernel. An old way of communication was superseded and my installation being so old could not clean up properly in order to cleanly apply the new way.