Congrats on your vulnerable system. I hope you're not doing anything important at all on it.
W7 is just fine. Daily driver on multiple machines, never been "taken over" or turned into a crypto miner or a hub for a bot network, never had a single virus or other issues.
[1] https://support.mozilla.org/en-US/kb/firefox-users-windows-7... [2] https://support.google.com/chrome/a/answer/7100626