And don't be fooled into thinking that Windows 7 is less secure because it isn't supported anymore. Windows isn't safe either way, it all depends on in how you use it.

Use uBlock Origin to block ads, trackers, and other third party insidious code (preferably use uMatrix as well if you're savvy enough). Enable your firewall. Don't download files from untrustworthy sources, etc.

Personally I only do financial transaction on Linux, and don't use a password manager on Windows. I actually only use Windows to play a game sporadically, or to use software that hasn't got an alternative on Linux, which is becoming quite rare.