You can check what apps cause a slowing of your boot, in Linux, with this command:
systemd-analyze blame
You should see something like the following
systemd-analyze blame
3.115s NetworkManager-wait-online.service
1.980s fwupd-refresh.service
1.928s fwupd.service
[…]
To disable NetworkManager-wait-online.service
, i.g., you can type: sudo systemctl disable NetworkManager-wait-online.service
.
other possible causes
Check also if your UUID (of swap partitions, i.g.) are correct. This can be a cause of a severe slowing.