That is really disappointing to read. We put a lot of effort into making Chrome start quickly. Back when I was responsible for Linux Chrome, I gave a lighting talk at the Ubuntu Developer Summit about it, and demoed Chrome starting faster than Gnome Calculator.
Hats off, Chrome starts instantly on my Debian machines. Even on a 10 years old, half dead Thinkpad it's just couple of seconds. This must be a Ubuntu/Snap specific issue.
firefox from the ubuntu repository is over 5 times faster to start. on any windows machine, it's almost the opposite. sorry to break the news. for what it's worth I still use it everyday... I usually start my browser once a day so it's not that big of a difference.