"is there a way to disable the idle for some users but leave enable for everyone else?" –
systemd-inhibit --what=idle tail -f /dev/null autostarted as a user service (from ~/.config/systemd/user/) should probably do it. I don't know if there is no better way. And note usually systemd-inhibit --what=idle … is what any user can run (possible problem: here), so if you want some users not to be able to do this on their own then you need to configure polkit accordingly, I guess.