Windows 7 is ending support in just two months. Which means no more support and updates should be expected from Microsoft. Upgrading to Windows 8.1 will only give another 3 years of support. Plus 8.1 may cost you money but probably can still get the free upgrade to Windows 10.
Windows 10 updates reach EOL too. Like if you go to look at your system information, if you don’t see current as of now version 1903, you won’t get updates until you update your Windows 10. Version 1803 EOL is a week from today so with 10, you will just need to update it to 1903 through Updates to extend the EOL.