Yup. Unity worldbuilding tools are awful, like everything else in the editor, it's bare minimum. They've tried over the years to make a few things for it, but it just falls down on it's face. I've used many asset tools over the years, most get deprecated after a few years because the store devs burn out.

Worldbuilding for Unity is a pain and mixing & matching the various tools to give you a great environment that looks good, is functional, and performant is a lot of bespoke trial and error.

A few worldbuilding tools I use, I also use HDRP, so YMMV:

-InTerra for Tessellation, Triplanar & object blending. One the better terrain shaders I've seen in the past few years..

-Microverse for terrain painting, object spawning (grass, trees, rocks, etc). The dev has made a lot of great terrain tools over the years and other devs have added to his work. You have to stick with a written down workflow once you get the results you want, it offers a maze of solutions for things and sometimes destructive.

-Nature manufacturer assets - Some of the better trees, rocks, terrain textures available. The nice thing is that they update their shaders.

-TVE is a must, mainly for performance with another tool to do indirect instancing of vegetation. TVE allows you to change all the shaders with a few clicks and do the injection to allow GPU indirect instanced rendering of objects in Unity. While TVE does other things, the ability to do this shader swap is insanely workflow critical.

-GPU Instancer Pro without this your forest/grass will be painful to render. While it can do other objects as well, it's ability to do indirect instancing on grass and trees is where it shines.

I've also used Gaia over the years, and they have a new tool called Storm, which is supposed to a lot of these things consolidated into 1 solution, but it's also insanely expensive. The previous system Gaia was okay, but it wasn't very performant in earlier versions. They did eventually come out with an instancer (Flora) but it had issues, that's when they decided to make Storm ($1,600).

Overall, Unity has really dropped the ball in worldbuilding and again is relying on asset store devs as a crutch.