The sandboxing is almost always better because it's an extra layer.

Even if you gain root inside the container, you're not necessarily even root on the host. So you have to exploit some software that has a known vulnerable library, trigger that in that single application that uses this particular library version, root or escape the container, and then root the host too.

The most likely outcome is it messes up your home folder and anything your user have access to, but more likely less.

Also, something with a known vulnerability doesn't mean it's triggerable. If you use say, a zip library and only use it to decompress your own assets, then it doesn't matter what bugs it has, it will only ever decompress that one known good zip file. It's only a problem if untrusted files gets involved that you can trick the user in causing them to be opened and trigger the exploit.

It's not ideal to have outdated dependencies, but the sandboxing helps a lot, and the fact only a few apps have known vulnerable libraries further reduces the attack surface. You start having to chain a lot of exploits to do anything meaningful, and at that point you target those kind of efforts to bigger more valuable targets.