It is if you're using Safari. I have two M1 Max MBPs. My personal machine runs Chrome, and my work machine runs Safari. I can run my work machine for well over a day doing iOS development in Xcode with an external monitor attached and not run out of battery. The personal machine will last almost all day (without a monitor attached) but not quite. I'm sure if I used Safari it would last much longer.

I've tried both. Safari does some neat tricks to reduce usage when pages are not active. But if you have a heavy webapp - you have a heavy webapp, and power will be used.

I hope you don't use Chrome for those web apps. Google stuff has terrible power efficiency.

Same effects both on Chrome and Safari.

But that's also irrelevant. Whole day of battery, if you don't use heavy apps is very different from whole day of battery.