"home user" asked:
> How do I rescue the rescue mode?
I think the root cause of the problem is that you have upgraded multiple times, and somewhere along the way (maybe around the F25 timeframe), the management of the rescue image and its grub entry got lost by the release and testing teams, and never removed or upgraded. It is still there and not getting cleaned up by any of the upgrades, but waay out of date and missing more than a few critical bits now. This is probably one of the casualties of allowing testing on VMs instead of real machines and insufficient release acceptance criteria. So for your situation, its dead, Jim.
You may be able to recover using the install media like you can in Ubuntu or Debian or Slackware, but I had no luck with keeping the filesystem contents intact using the default one-disk layout on Fedora 30. I probably didn't have the obscure document available on how to actually do this, so YMMV of course.
Failing that and assuming that you don;t have a petabyte or so of LVM content, it may be possible to mount the existing LVM volumes from the install media, in order to copy off a backup of what you need to keep undamaged, and reinstall from scratch.