No, battery life isn't on par.
The only way to get the battery life Framework advertised is on Windows' 'Ultra Efficiency' mode which cuts CPU performance by 25-50%, lowers brightness by 30% and deprioritizes everything in the background to such an extreme that responsiveness of those is measured in seconds.
It is not comparable at all to M-series or Snapdragon laptops happily chugging along at full capability and getting (compared to AMD / Intel) stellar battery life.
They're talking about the new model announced, with a larger battery and ARM architecture. Not released yet, I don't think.
I’m pretty sure macOS safari doesn’t execute JavaScript on background windows/tabs.
When I play Bitburner, if I want to run it in the background, I have to run the game on Firefox or chrome. It’s a shame because safari actually gives best performance by quite a large margin.