No. Literally no one uses UTC or leap seconds for that. The only people who need to pay attention to sun angle are astronomers, and they use their own system b

No. Literally no one uses UTC or leap seconds for that. The only people who need to pay attention to sun angle are astronomers, and they use their own system based on TAI. So you are arguing to continue rejiggering a complex and error-prone system that benefits exactly nobody.