How paranoid should one be of, say for example, a wasm vulnerability exploited on zero day by a bad JS ad?

I am scared for my parents to get exposed to this kind of thing from bad ad network actors. Does anyone have some practical concrete recommendations they took? Like I don't think they can install ublock origin and whitelist sites on demand in Firefox they way I do.

The only practical thing right now is to make sure they don't have the money on device and have 2 fac for email and bank accounts. But every now and then there are phishing attamepts that they could fall prey to.