How to update Ubuntu without network connection (using only connected Windows machine)

My ubuntu system no longer connects to the internet, I suspect due to lack of updates since I haven't used it for almost two years. However, I now need to use it with internet again, but it fails to connect to both wired and wireless networks (these have changed at home since I last used it due to an upgrade to glass fiber connection, I've tried to connect both at home and at work without success). It might be noteworthy that the Ubuntu system is on the second partition of a laptop that is fully capable of connecting to the internet (both wired and wireless) when I run its Windows partition, so I don't think it's failure to connect has anything to do with the hardware. I am aware that there is something called apt-offline, but the tutorials for this seem to require having access to a machine that is also running some kind of Linux OS and that is connected to the internet. I don't have access to that, but I do have access to multiple Windows 10 machines that have internet access and USB data carriers. I'm struggling to get the files I need on a USB stick due to the Linux terminology whilst using a Windows system. Can someone explain in beginner friendly terms how to update my Ubuntu system using one of my Windows machines? Thank you so much for your time.