"the player still respawns"

-- If you want to prevent the player from respawning, you can remove the player:LoadCharacter() line. Here's how you can modify the script:

local Players = game:GetService("Players")
local UserInputService = game:GetService("UserInputService")
local buttonS = script.Parent.Black.Respawn
local redeploytext = script.Parent.Black.REDEPLOY
local countdown = 10
local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()

character:WaitForChild("Humanoid").Died:Connect(function()
	script.Parent.Enabled = true
	player.RespawnLocation = nil
	while countdown >= 0 do
		redeploytext.Text = "("..countdown..") REDEPLOY"
		task.wait(1)
		countdown = countdown - 1
	end
	redeploytext.Text = "      TO REDEPLOY"
	buttonS.Visible = true
end)

UserInputService.InputBegan:Connect(function(input)
	if input.KeyCode == Enum.KeyCode.Space then
		-- player:LoadCharacter()  -- remove this line to prevent respawning
		script.Parent.Enabled = false
		buttonS.Visible = false
	end
end)