Unable to lower(sculpt down) terrain

Cant lower terrain via sculpt tool unless of course I create a new project, and wondering what about my current project would stop me from doing this ?
I doubts its corrupt as everything else works perfectly although a year plus ago when I was rather , green, I created my 4 tile world comp terrains , each at 5101x5101 as I was just trying to create my world based on srt real world data I’d downloaded, much later I realized they weren’t the ‘recommended size’, but does that really matter ?

So is this fixable ? I tried raising terrain in side view , seeing its below the horizontal line, but that didn’ t have any effect.

No, what matters is what Z scale was used on import, and if the tile component size is currenly still in existence.

my suggestion is (as almost always): start again.

  1. load the 4 tiles.
  2. enter landscape mode
  3. export the heightmap.
  4. load in Krita if below 10,000x10,000 pixel and cut it up to whatever reccomended size.
    use GitHub - libvips/nip2: A spreadsheet-like GUI for libvips. for bigger stuff / faster processing.
  5. import new tiles.
  6. move actors to new tiles.
  7. delete old tiles.

No luck and ty for assist to help get this working, but I deciderd to leave 5101 given it has nothing to do with my issue, and loaded into new project and no luck same problem.