My Mac Air M4 13 is draining battery in 8 hours while using light chrome and safari. I am only using google docs and youtube. This laptop is less than 2 months old.
Chrome is not "light usage" and neither are Google docs. Chrome is a fast battery drainer on both Mac and Windows laptops.

Use your power supply when using "Google anything" to satisfy their power demands. The Brave browser uses the same engine as Chrome but with far less overhead
Any viewing of videos works both the CPU and GPU quite hard. Not light use.
Some web sites are now very greedy as well. All that advert animation comes at a cost. I saw an Amazon page run down the battery by 50% on one of my Macbook Pro in 50 minutes simple by leaving it open in the background while I was away from the computer.
Activity Monitor, included with macOS, can help you spot high-demand activities:
View energy consumption in Activity Monitor on Mac - Apple Support
Before using Activity Monitor for the first time, make sure its "View' option is set to "All Processes" to get the full picture of energy usage.