I have experienced a slight increase in the startup time of browser from when it was just launched. Also the present edge browser consumes lot of disk and cpu on startup for atleast 3 seconds, which is not good for performance. My battery estimates immediately lower down from 7hrs to 4hrs. I am partially statisfied with the legacy browser as its startup time was less than 1 sec, altough sometimes it was unresponsive. Kindly provide a flag to load service workers when needed.
Also one suggestion is that instead of loading everything then putting it to the display, instead create browser window frame first then followed by browser frame then all the needed chunk of loading new page or specific ones. It would then be more fast and responsive to the user on startup.