Sigmar also tends to err toward 2K but often as not getting your feet wet and trying out the game at smaller point levels and building up your force steadily not only gives you lessons in the mechanics but also helps you keep up - building 2K force before playing can be wearing on the hands and moral
Also make sure you get the Battletome for Seraphon (er lizardmen) as that will give you most of the info you need to play them. Back that up with the Generals Handbook 2018 and then you can either get the big rule book (mostly full of lore) or use the PDF on the warhammer website for the core rules.
You might also want to kepe an eye on the Malign Sorcery boxed set as the Endless Spells are proving very popular in many clubs/groups. The Realm based stuff is a bit more hit and miss, but the endless spells are a good investment and the MS boxed set is cheaper than a getting started and gives you all the models and rules and kit you need (barring Balewind Vortex model). Seraphon being a magic heavy army often as not, the Endless spells are a neat and powerful addition when used right.
After that the getting started kit is a very good - well - starting point.