For completeness, here are the timings for the other snaps:
gnome-calculator
First Run
snap run --trace-exec: https://pastebin.ubuntu.com/p/B6PQz73cSr/
Actual desktop-launch elapsed time: 0.533724216
Actual total startup time: 2.07
chromium
First Run
snap run --trace-exec: https://pastebin.ubuntu.com/p/hTmCMgwW5D/
Actual desktop-launch elapsed time: 0.643954821
Actual total startup time: 4.64
gnome-logs
First Run
snap run --trace-exec: https://pastebin.ubuntu.com/p/6jNbhD3jbw/
Actual desktop-launch elapsed time: 0.510977055
Actual total startup time: 2.60
irccloud-desktop
First Run
snap run --trace-exec: https://pastebin.ubuntu.com/p/JMqqTy2Y2B/
Actual desktop-launch elapsed time: 0.482481699
Actual total startup time: 3.62