Password Managers help but aren't a panacea. A determined and/or well funded, or exceptionally advanced hacker can still blow through them. There are technologies far more advanced that can bypass virtually any security setup so plugging your PC in itself can place it at risk.
Unless you put a KVAR on your home circuits (Shunt Capacitor). Plug your PC Into an Isolation Transformer with a Material 31 Choke on the Isolation Transformers cord, they are going to hop in through your 60Hz connection and/or siphon 60Hz Sinewave variances from your Smart Meter and extrapolate your activities at a granular level. Or even better, put a Sinetamer on your whole panel, then a Isolation Transformer on your PC and call it a day.
So much of this stuff varies between feel good technology, security theater and discouraging low grade attackers looking for low hanging fruit. Against anything more serious, you are toast unless you know what you are doing. So use a password manager understanding what you are protecting against, without any illusions it insulates you from serious problems.