How do you manage computer security in your devices?

I feel that just common sense isn't enough nowadays, because of several reasons:

- Browsers especially (even if you disable JavaScript, which is often not feasible in many sites), but also email clients, torrent clients... can all be exploited somewhat easily.
- Some games require kernel-level anti-cheats, which have complete access to your computer. Even if you trust the developer, these kernel drivers are often buggy and can be leveraged by malware.
- Legitimate programs or Steam games might receive malicious updates if the developer or their supply chain is compromised.
- If you use third-party dependencies for development, you might also be compromised if any of them (or their recursive dependencies) are malicious, not uncommon in ecosystems like npm.
- If you play doujin games or eroge, you often have to download them from random untrusted sources.

I've concluded that it's not really possible to trust a computer if you use it for activities like these.

I'm thinking about getting a second device only for sensitive stuff, like banking, shopping and managing passwords. It seems a bit of a hassle, but I can't think of any other way.