Welcome!
Use Activity Monitor
View information about Mac processes in Activity Monitor - Apple Support
to see if any web sites you have open are using a lot of processor cycles and energy. I once left the Amazon home page open in a background tab on my idling Macbook Pro and returned to find the battery runtime had plummeted to a third of what it should have been for the time period involved. Activity Monitor showed that the Amazon tab was using more resources and energy than the other 12 tabs combined. Closing Amazon when I was done fixed that. Other sites have done the same thing.
This is an example of how tabs in Safari use processor cycles, from a few minutes ago on my Macbook Pro 2012. Each represents an open Apple forum tab or Apple support pages. They use almost no percentage of cycles:
WhenI had the Amazon issue, its tab was using over 20% of cycles. No wonder my battery drained! When I closed the Amazon tab, the rate of battery drain returned to normal.
Are you running any anti-virus software or so-called "cleaning" apps? They will shorten runtime and cause a myriad of other issues. They are not needed. Let your Mac be a Mac.
Remember not to underestimate the demands of some apparently simple tasks. Streaming video, either within a browser, through an App, or through FaceTime will demand a huge a mount of your Mac's capacity. Videoconferencing likewise is high-demand.
