Terrain generator not working as intended

[syntaqs (syntax)]

You can write your topic however you want, but you need to answer these questions:

1. What do you want to achieve? Keep it simple and clear!

The terrain generator I scripted works, but I want to prevent these holes from appearing, and these weird lines. I would appreciate any help.

2. What is the issue? Include screenshots / videos if possible!
   I tried breaking the loop to prevent these massive holes from happening when you stop generating the terrain, but instead, it made the problem worse.
   

   
   
   
   
   
   
   

3. What solutions have you tried so far? Did you look for solutions on the Developer Hub?

function generate()
local positions = {}
	local ypos

	local totalx
	local totalz
	local zoom = 75
	local height = 100
	local size = 2048
	for x = -30,size do
		for z = -30,size do
			
			local pos = CFrame.new(x,math.noise(x/zoom,z/zoom)*height+25,z)
			ypos = pos.Y
			table.insert(positions,pos)
			local size = Vector3.new(1,1,1)
			if (pos.Y>math.random(60,80)) then
				workspace.Terrain:FillBlock(pos,size,Enum.Material.Rock)
			elseif (pos.Y<math.random(1,5)) then
				workspace.Terrain:FillBlock(pos,size,Enum.Material.LeafyGrass)
			else
				workspace.Terrain:FillBlock(pos,size,Enum.Material.Grass)

			end
			if(z>=1000-260 and pos.Y<2) then
				totalz = z
				break
			end
		end
		if(x>=1000 and ypos<2) then
			totalx = x
			break
		end
	end
	print(totalx,totalz)
	
	workspace.Terrain:FillBlock(CFrame.new(totalx/2,30,totalz/2),Vector3.new(totalx*2,10,totalz*2),Enum.Material.Grass)
	workspace.Terrain:FillBlock(CFrame.new(totalx/2,-2,totalz/2),Vector3.new(totalx*5,1,totalz*5),Enum.Material.Sand)
	workspace.Terrain:FillBlock(CFrame.new(totalx/2,5,totalz/2),Vector3.new(totalx*5,5,totalz*5),Enum.Material.Water)
end

generate()

Any help is appreciated