Samsung adds an advertising screen overlay on my old galaxy if i update it. So I need to keep it to factory default and not update it. They claim they don't do

Samsung adds an advertising screen overlay on my old galaxy if i update it. So I need to keep it to factory default and not update it. They claim they don't do that, and it's 3rd party apps. Perhaps, but it's apps they force onto users with their update process. I imagine I'm not the only one blocking updates to avoid ads.