Can a portable power station be used as an uninterruptible power supply?

Yes, a portable power station can be used as an uninterruptible power supply. Many portable power stations come with UPS features, like automatic switchover when power loss is detected.

What accessories do you need for a portable power station?

One of the most common accessories is going to be a cord to connect to similar power stations in series, often times doubling your power output. Some portable power stations have a light bar built into the housing, which is useful for seeing at night. Anker’s Solix C300 also includes a pop-up camping light.

Is a 3000W power supply a good choice?

Specs-wise, it's well-equipped for power back-up, with a 3000W continuous power output, and also includes a Uninterruptable Power Supply features, which is essential for units of this size. There are improvements we'd make here and there, including a not particularly good app and AC port placement to the front.