I shot on the NX1/NX500 as my primary cameras from 2014-2019, before I moved onto an S1/GH5 combo which I'm still happily using currently. I couldn't care less about autofocus (I primarily shoot vintage contax zeiss or anamorphic) so the S1 is an excellent successor to the NX1 for my needs, especially after it's semi-recent updates of 6k internal, pro res raw, output, etc.
I still love the NX1 and I don't think I'll ever sell it, but while it still has an incredibly detailed image, as amazing as it was back in 2014, no 10-bit modes, no 4k60, no IBIS, no log profile, really strong rolling shutter in 4k, and low light falling off a cliff above 800 ISO all keep it on the shelf for me most of the time these days compared to the S1, which is exceedingly strong in all of those areas.