[NAME]  Yes, there is a Killer Intelligence Center app listed on Startup tab in Task Manager, but with all the Killer services disabled in services.msc, I don't think that Startup app can run, but certainly can't hurt to disable it. It may be time to "byte" the bullet. Image the boot drive and save the image on an external drive. Then wipe the boot drive and do a clean install of Win 10 or Win 11. Test printers' connectivity before you reinstall too many apps. If things are working properly, continue installing the rest of the apps. If the same problem recurs after the clean install, you can always re-image the drive so you don't have to reinstall all the apps again...
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 Dell XPS 8940, Windows 10. All printers show as "not connected" in Control Panel Devices or Settings, printers and scanners, even the phantom printers (like, "Microsoft Print to PDF" or "OneNote for Windows 10". 
XPS 8940, network, phantom printer all show as not connected