if i try to change a welds orientation it destroys it self how can i fix this?

Sorry I don't know anything about this but maybe looking through this source code from a plugin can help( i didn't make this):

local plugin = PluginManager():CreatePlugin()
local button = plugin:CreateToolbar("GeomTools"):CreateButton("Transform","Freezes attachments for transformations","rbxassetid://606821411")
local mouse = plugin:GetMouse()

---------------[[ Main ]]---------------

local function partMoved(p)
    -- arbitrary wait fixes everything
    wait()
    local part = p.Part
    local originCFrame = p.OriginCFrame
    local originSize = p.OriginSize
    local newCFrame = part.CFrame
    for _, a in pairs(p.Attachments) do
        local attachment = a.Attachment
        local attachmentOriginCFrame = CFrame.new(a.OriginalPosition) * CFrame.Angles(math.rad(a.OriginalRotation.X), math.rad(a.OriginalRotation.Y), math.rad(a.OriginalRotation.Z))

        local correctedCFrame = newCFrame:toObjectSpace(originCFrame) * attachmentOriginCFrame
        attachment.Position = correctedCFrame.p
        local x, y, z = correctedCFrame:toEulerAnglesXYZ()
        attachment.Rotation = Vector3.new(math.deg(x), math.deg(y), math.deg(z))
    end
end


---------------[[ Collect Parts ]]---------------

local parts = {}

local function tableContains(list, instance)
    for _, v in pairs(list) do
        if v == instance then
            return true
        end
    end
    return false
end

local function getAttachments(part)
    local attachments = {}
    for _, v in pairs(part:GetChildren()) do
        if v:IsA("Attachment") then
            table.insert(attachments, {Attachment = v, OriginalPosition = v.Position, OriginalRotation = v.Rotation})
        end
    end
    return attachments
end

local function getParts(instanceList, partList, gottenParts)
    partList = partList or {}
    gottenParts = gottenParts or {}
    for _, v in pairs(instanceList) do
        if v:IsA("BasePart") and not tableContains(gottenParts, v) then
            table.insert(gottenParts, v)
            local part = {Part = v, OriginCFrame = v.CFrame, OriginSize = v.Size, Attachments = getAttachments(v)}
            if #part.Attachments > 0 then
                part.UpdateConnection = v.Changed:connect(function() partMoved(part) end)
                table.insert(partList, part)
            end
        end
        getParts(v:GetChildren(), partList, gottenParts)
    end
    return partList
end

local function disconnectUpdates()
    for _, part in pairs(parts) do
        part.UpdateConnection:disconnect()
    end
    parts = {}
end
---------------[[ Inputs ]]---------------

local function updateSelection()
    if active then
        disconnectUpdates()
        parts = getParts(game.Selection:Get())
    end
end
game.Selection.SelectionChanged:connect(updateSelection)


mouse.KeyDown:connect(function(key) --27 escape, 13 enter
    if not active then
        return
    end

    key = string.byte(string.lower(key))
    if key == 27 then
        active = false
        button:SetActive(false)
    end
end)

plugin.Deactivation:connect(function()
--  active = false
--  button:SetActive(false)
end)

button.Click:connect(function()
    active = not active
    local active2 = active
    plugin:Activate(active)
    active = active2
    button:SetActive(active)
    if active then
        updateSelection()
        warn("Freeze attachments plugin active. Transforming and resizing parts will not affect the absolute positions of their attachments.")      
    else
        disconnectUpdates()
        warn("Freeze attachments plugin disabled.")
    end
end)