If your external drive crashed during a recovery that’s really bad luck and extremely unlikely to happen.
Plain and simple it doesn’t matter then what software you were using, TimeMachine, SuperDuper, Carbon Copy Cloner, etc, etc, if the drive has a hardware failure the software isn’t going to make any difference.
I run TimeMachine as my primary backup. I own both SuperDuper and Carbon Copy Cloner. Haven’t really used either in a few years. There big advantage was the ability to boot off the backup drive.
TimeMachine doesn’t do the boot thing, and way back when (OSX lion I think) Apple added a recovery partition to the main drive. You can also start a Mac now with recovery mode over the Internet, you can also create a bootable thumb drive.
Yes booting off the internet or even a thumb drive is slow, but they both work, and let’s face it, if you’re at that point it’s disaster mode, time isn’t the primary concern.
I’ve never had any problems with later releases of TimeMachine so I dropped the other backups and use TimeMachine at least weekly for individual file recovery. I’ve never had any problems. Many of the old-time Mac users had problems with the old version of TimeMachine and especially the users of Apple’s old Time Capsule hardware have a bad taste in their mouths.
I run two TM drives all the time. I also use BackBlaze to keep offsite backups for disaster recovery, if your house or office burns down having twenty backup drives in the same location doesn’t help much.