None of my Win7 machines tries to harass me about updating to Win10. I know XP had a scheduled task to annoy you, which could be deleted. Your Win7 probably has a similar thing.
To keep Win7 fully up to date, firstly you need to install the ESU patch, which gives updates from 2020 to 2023. However this only works if you were completely up to date before the shutdown. Otherwise you need to install 2 KBs.
Now, after 2023, a certain site gets more updates monthly. This is what I use, and so all my numerous Win7 machine are all security-updated to the latest possible.
I don't want to get the site owner in trouble, so I won't say the URL. But you can PM me if you like.
As for Ryzen, I don't know anything about that, or what effect it might have.
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Talking about XP, when I started updating my XP machines several years ago I noticed that Defender was an option, unfortunately there were no updates available, and it kept wanting to be updated, so I had no option but to uninstall it.