Intel MacBook Pro 2020 battery life much shorter than advertised

I'd recommend clicking on the battery icon in your menubar. This is a quick way to determine which applications or features are consuming the most battery.

Here's mine:

Using significant energy

Also, in addition to the CPU usage stats, Activity Monitor includes an "Energy" tab that includes columns for "Energy Impact" and "12 hr Power" that are worth investigating.

Activity Monitor "Energy" tab