I had luck with WD-40. Bought Switch ca. 1 year after Zelda, small drift was mitigatable through whiggling the joys a long time. Then, Witcher, I had enough of it and sprayed a tiny amount into both. Working like a Charm since then. YMMV
I replaced mine with sticks using hall effect sensors. The stick replacement process isn't easy, but also not too bad. When I first opened my joycon, a spring flew across the room and I had a hell of a time trying to find it.
