As far as eating up energy and memory, I feel the painfully slow Mac problems. I think I have a pretty good solution for you, I hope :) After putting in real work and time with 4 different browsers over the course of about 6 days, noting my device's performance under normal working conditions, and being flexible with workflows in each browser, I came back to Chrome.
I continued searching high and low for an answer to my dilemma with no luck because my 2017 Macbook Pro was... about to be tossed out my fifth story apartment. I ultimately came up with my own little solution, implementing two wonderful plugins. They also added some benefits that I didn't even know I needed, which is something that'll help you automatically saving your windows' state of tabs, while also along you to save collections of tabs manually.
I don't know how I've survived this long...
"Chrome Tab Hoarder" and "Memory Efficiency" Achievements Unlocked!
Confession - I knew my memory issues were caused by the fact that I had 15 browser tabs open. I can have triple that open now, no problem.
Get the Toby Chrome extension to automatically save any and all browsing window states whether your computer stroked out or you quit Chrome on purpose. It's even better than what I was originally searching for because you can save (and edit at any point) Collections of tabs. This is by far my most used and favorite thing that I've discovered in 2020 (along with my web design software, Figma, and upgraded web development workflow).
The perfect companion extension for Toby is called The Great Suspender. It will cause you to yell at the sky screaming profanities a lot less because your computer will run SO much better. Suspended tabs use significantly less energy and memory. If you have tabs open and don't use them within 30 minutes, it'll stay there in your tabs, but be suspended and not use resources. When you click on the tab, it reloads. It won't suspend any tabs that have input fields with information in them or ones that actively play videos or sounds. You have options to not suspend any tabs from a particular domain, particular URLs (I don't suspend Gmail, ClickUp, and some others), customize the amount of time before suspending a tab, etc
I hope this helps some people! It may sound like a lot but give it an honest couple of days and see what you think, especially those of us who are tab hoarders 😬.
I literally have 46 tabs open right now between two different windows - oops 🥺 My 3-year-old MacBook Pro has that plus Photoshop and 6 other open apps. My embarrassing number of tabs (let's not talk about it) wasn't even a possibility before, neither was saving them.