There were times over the years where I wanted to write this very title. It's nerve-racking.
I was not educated enough to see it lts was for me, so I never tried. I hear nothing but good things about it from other forum users. I lived and died with the kernel updates. But you had a long break with no stress at all. Maybe just a hiccup that will go away?
I ran solus off beat-up usb drives, and old external, and an old HDD for years. A factor? I ran an ancient underpowered two-core that I maxed out with tasks. Factor? A mobo since 2009. Factor? Don't know if it's yes or no. Upgraded all early this summer and haven't experienced a freeze yet except occasional keyboard stutter and I fixed that.
Your inxi shows a robust system to me. Hardware was my issue in the end. I'm not saying it's yours but lts has mostly served you well, you said. I always think there's more factors with these things.