LTS != stable. On average there's a LTS upgrade every 7 days. Mainline's release cadence is 3 months.

There are a lot of changes going into longterm supported branches: 10s of thousands of patches that were developed and tested against a different codebase written many years into the future are being backpatched into up to 6 year older codebase on top of other randomly picked patches with a hope/assumption that everything will work out the same way it does on mainline. It often does, but uh...

Mainline gets months of testing for each final release, stable releases get about a week of testing at most.

I definitely put my trust into mainline as a regular user. I also like the support for my HW to keep improving as a regular user, which mostly happens with mainline, if I have recent HW.

I view long term supported releases as speciality release useful for some very specific situations, like for device manufacturers who dislike instability of internal kernel apis and can validate each such release against extensive testsuite before pushing it to users. I would not run it as a normal user. (maybe with an offset of several releases, to have more testing for each stable release by others before I move to it)

Well, given how frequently kernel upgrades break stuff, if what you're saying about LTS reliability is true, I suppose the only reasonable solution for regular users is to never update their kernel. Or use a distro which holds kernel releases back for months to do their own validation, like Ubuntu and Debian.

I have different experience. I'm on the same Arch install (migrated across 3 different computers) for 15 years, going through almost every minor version kernel update during that time, and I never saw breakage of my system caused by the kernel update. Maybe I'm just lucky picking HW. :)