I been on all tier planets up to 5. Digging from top to core, digging in different horizontal direction for hours, but can not find any cave system. All cave i find are small isolated holes, and i do not find any openings in the surface either.
It was a big part of the game in pre, to explore the huge underground and i rely miss it.
Am i just unlucky, or are the big cavesystem gone??
Sounds like you’re unlucky. I have found some really large caves completely underground along with the various small pockets, but also a good number of large caverns with external openings on all Tiers of worlds