It is not really a probleem
waiting every time at start-up.
I use the kodi device not only for IPTV
also for watching movies, or other streams. It is not dedicated for IPTV, so it is used everyday. Also other guys at forums did told me, when I had still old hardware, that the network drivers are slow. And if i would buy new hardware it would be no issue anymore. So I'm surprised actually
So i understand now it is normal that I have to set a delay, if you using iptv. Maybe there are other add-ons, or part of libreelec which needs network at start-up. So network must always be active at startup