A video call starts breaking up just as Windows begins downloading something. It is tempting to turn the update settings down immediately. First check whether the busy transfer is actually an update: a cloud upload or another device could be competing for the same connection.
Find the relevant control
In Windows 11, open Settings, Windows Update, Advanced options, then Delivery Optimization. Its download limits do not apply to downloads you start manually in Windows Update or Microsoft Store. Keep that exception in mind when checking whether a change worked.
Suppose you set a background limit, then press the button to download an update yourself. A faster transfer does not necessarily mean your setting was lost. You have changed the conditions of the test. Write down what you adjusted and whether the transfer started automatically or by your action.
Change one thing and check again
Choose a modest limit appropriate to your connection, leaving time for updates to finish. Avoid changing several download and sharing options at once: if the call improves, you would not know which change helped. Check the next comparable background download, rather than relying on a single moment of silence.
Sharing with other PCs is a separate choice. Turning it off still allows updates from Microsoft; it is not an off switch for Windows Update. On a managed work computer, ask the administrator about unavailable controls.
After the busy period, review your limit and make sure updates can complete. If calls remain poor when no update is downloading, investigate the other traffic instead of repeatedly tightening this one setting. Record that result too: ruling out an assumed cause saves another round of changes tomorrow.