You are correct that Win7 is not suitable for internet browsing or other online activities. It's wildly insecure. However, it runs some old software just fine, offline.
I was thinking about running it under a sandbox if I need to download anything, but not sure how I would get the download out of the sandbox session onto the computer, but I can find out how later if sandboxing would be a viable safe way to connect windows 7 to internet. I do have one game that is online, which has frequent updates, but don’t really need to keep that one if there is no safe way to connect 7 to internet?