Should be absolutely no problem with the 8th Gen. processors. As far as I know, it needed a BIOS update the other way around (i.e. for 9th gen. on z370). So I think this is a good choice. Especially since the newer chipset will surely remain forward compatible/supported for a bit longer. But I'm no expert ;)

Thank you! I decided to go for the 9th generation after all :)