Slow Ubuntu Bootup Troubleshooting

To analyze the reasons slowing down Ubuntu bootup, please use systemd-analyze cmd. 

systemd-analyze time
Startup finished in 5.027s (kernel) + 11.220s (userspace) = 16.247s
graphical.target reached after 11.194s in userspace
To sort modules by time taken during boot, use
systemd-analyze blame
We can see snap modules took quite long to load. But snap are loading in parallel and doesn't block others. We can see critical path:
systemd-analyze critical-chain
graphical.target @11.194s
For me, removing a USB card reader helps, due to BIOS/UEFI?