So, how you bring in more subdivision\tessellation to a landscape you have already created is to resample the landscape by going to the Landscape panel then choose the *Manage Mode
(Only if not using World Partition this can be done. With WP you don’t see resample)
So, here you will see a tool option called Resample select that, and you now should see something like this (UE5 might look different)
Now you choose to resample in the Resize mode , and change these values accordingly to the recommended sizes based on the actual resolution of your heightmap:
“If you are not using a heightmap, then you don’t have to stick the a min/max resolution”
These are the recommended landscape sizes:
What you want to do is to give the landscape smaller components, and more components in total.
So set the component size to a lower value, and increase the amount of components.
But you need make sure you don’t go above the resolution of you heightmap if using one.
If you don’t use a heightmap, then you can set the resolution you want to…
Try using 2x2 sections for performance reasons, but i would try both. And also try to adjust the component size and amount to get as little amount of total components as possible, but still have enough to be able to sculpt without the jagged triangle shapes…
Also look this post: Landscape grid resizing - Development / Rendering - Epic Developer Community Forums (unrealengine.com)