In Endwalkers, for causal players, there are:
Island Sanctuary
Seasonal events
MSQ and Sidequests
Dungeons
Custom Deliveries
Beast tribes
Eureka Orthos
Variant dungeons.

For hard-core players, there are:
12 Savage raids
2 Ultimates
3 Criterion Savages

For mid-core players, there are:
7 Extreme trials
3 Criterion dungeons
5 Unreal trials (not exactly new content)

I think having more mid-core content, can help players transition from causal to hard-core content, so it is not exactly only helpful for mid-core players only.