I have recently upgraded my notebook from leap 42.3 to 15.0 (yes, I am a tad behind, sorry!) and I've found that boot takes much much longer than 42.3 or even than my laptop running Tumbleweed.
I did a bit of research and I think there are two suspects:

# systemd-analyze blame  | head -20
    1min 30.131s clamd.service
         27.796s plymouth-quit-wait.service
         12.243s ca-certificates.service
          7.116s postfix.service
          6.817s display-manager.service
          6.410s SuSEfirewall2_init.service
          6.368s lvm2-monitor.service
          5.854s apparmor.service
          5.109s initrd-switch-root.service
          4.087s nscd.service
          4.080s alsa-restore.service
          3.995s bluetooth.service
          3.253s btrfsmaintenance-refresh.service
          2.550s windscribe.service
          2.175s polkit.service
          1.755s systemd-udevd.service
          1.634s fwupd.service
          1.630s SuSEfirewall2.service
          1.447s colord.service
          1.198s systemd-journal-flush.service
clamd.service seems to take remarkably long. My question is, what can I do to fix this? or, where can I find more information about this problem?

In the second place:
# grep resume /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda2 splash=silent quiet showopts resume=/dev/sda2 splash=silent quiet showopts resume=/dev/sda2 splash=silent quiet showopts resume=/dev/sda2 splash=silent quiet showopts"
(where sda2 is the root partition)
This looks rather repetitive, is it supposed to be like this? It doesn't look quite right. I've compared it to my Tumbleweed result running the same command and it doesn't repeat the same parameter, but I don't dare chopping it off without asking first.

Perhaps these are all irrelevant, and I should be looking elsewhere? Leap does boot and runs smoothly, but it takes a surprisingly long time to do so.

Thank you in advance for all the help and ideas that you can kindly provide.