I can't figure out how to slow down the player when they fall

I changed the script to this now:

local part = script.Parent-- Get the part that the player will touch
local RunService = game:GetService("RunService")

part.Touched:Connect(function(otherpart) -- Connect to the part's touched event
	local hrp = otherpart.Parent:FindFirstChild("HumanoidRootPart") -- Find the player's HumanoidRootPart

	local bodyvelocity = hrp:FindFirstChildWhichIsA("BodyVelocity")	-- Check if the player has a body velocity attached
	if hrp and not bodyvelocity then
		local newvalue = Instance.new("BodyVelocity") -- Attach a body velocity to the player's humanoid root part to give them an upward push
		newvalue.Velocity = Vector3.new(0, -25, 0) -- give an upward velocity of 10000 in the Y-axis
		newvalue.MaxForce = Vector3.new(10000, 10000, 10000) -- Set the max force to be able to apply to the player's humanoid rootpart
		newvalue.P = 5000 -- Set the damping property of the body velocity to 5000
		newvalue.Parent = hrp -- Parent the body velocity to the player's humanoid root part
		-- Function to be run every render step to check if the player is within 100 studs of the ground
		
		local function onHeartbeat()
			if hrp.Position.Y <= 100 then -- Check if the player's humanoid root part is within 100 studs of the ground
				hrp.BodyVelocity.Velocity = Vector3.new(0,0,0) -- Set the player's velocity to (0,0,0)
				hrp.BodyVelocity.MaxForce = Vector3.new(0,0,0) -- Set the max force to (0,0,0) to stop applying the upward force
				newvalue:Destroy() -- Remove the bodyvelocity
				RunService:RemoveHeartbeat(onHeartbeat) -- Remove the heartbeat event
			end
		end

		-- Bind the heart beat function to the render step
		RunService:BindToRenderStep("slowFall", Enum.RenderPriority.First.Value, onHeartbeat)
	end
end)

--This will effectively slow down their fall as they get closer to the ground.

It works, however I have another problem now. I can’t get the new value to get removed/destroyed once the player reaches a certain point. I’m glad I can at least slow the player’s fall though.