I really like Manjaro. I’ve been running it on my personal computer for many years now, however, I would not recommend it for grandma’s computer. Their “delayed and curated” release strategy mostly just works but when it doesn’t it doesn’t. As someone mentioned elsewhere in the comments I would lean towards Red Hat or Debian for more mindless distros. I’ve administered thousands of Debian package updates and distro upgrades and it’s so stable. We don’t deserve Debian.