Interesting, I made the opposite observations on two different Macs. Safari, Edge, Chrome & Brave are all less resource hungry for me than Arc, including way worse energy impact / battery drain, unfortunately.

And I'm not alone either, looking at Reddit & Discord in the past.

Made me also switch away again recently. Would love to see them focus more on that instead of all those gimmicks. (Actually expected that before seeing them ship 1.0.)

Also, the way they handle extensions and especially the recent changes getting rid of the extension bar top right are/were also not great.