Here's what I think. In a world with sea levels 2 km above, you'll have mountainous plateaus and mountainous Islands as the dominant land form rather than plains.Kind of, since in a panarchist system, rather than moving to a place that's more closely aligned to your views, you simply change your political membership, but it's close enough.
States based on lineages and people rather than territory tended to be in mountain areas or islands, so by doing this they becomes the dominant state form and modernity most likely emerges from them.
States that are territorial but also place a great emphacis on people and lineages are the states that developed in areas with low population densities and nomad states. So giving those mountains an ecology that can support complex societies without strict agriculture could also help and mountains themselves favour pastoralism while NorthWest Pacific coast fjords favoured foraging, hunting and fishing to such an extent as to support complex societies.
As for whether such societies can support things like sewage systems and the like. We have to remember that modernity was invented OTL in Europe, in states where tho territorial had a national identity and considered itself to rule over specific nations/peoples. So it is entirely possible that as modernity in OTL was developed among territorial states that just happened to rule over homogenous nations, modernity in this ur world would be created by lineage based states that just so happen to rule over a fairly large continuous territory.
Also, stuff like sewages were developed explicitly from and for territorial states. It is entirely possible that like in OTL were suckaway pit systems are the exception, in this world suckaway pits would dominate and sewage systems would be the exception, occuring in highly developed, fairly homogenous and/or densely populated areas.