5 minutes, 5 hours, doesn't matter. And it does actually go to sleep when closed.
cinnamon-screensaver/zara,now 6.4.1+zara amd64 [installed]

I don't see any errors at all.
Dec 08 23:17:01 Mint-Yoga CRON[10491]: (root) CMD (cd / && run-parts --report /etc/cron.hourly)
Dec 08 23:17:01 Mint-Yoga CRON[10490]: pam_unix(cron:session): session closed for user root
Dec 08 23:17:18 Mint-Yoga dbus-daemon[780]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.190' (uid=1000 pid=10482 comm="/usr/bin/gnome-screenshot --gapplication-service" label="unconfined")
Dec 08 23:17:18 Mint-Yoga systemd[1]: Starting systemd-hostnamed.service - Hostname Service...
Dec 08 23:17:18 Mint-Yoga dbus-daemon[780]: [system] Successfully activated service 'org.freedesktop.hostname1'
Dec 08 23:17:18 Mint-Yoga systemd[1]: Started systemd-hostnamed.service - Hostname Service.
Dec 08 23:17:51 Mint-Yoga systemd-resolved[723]: Clock change detected. Flushing caches.
Dec 08 23:17:51 Mint-Yoga systemd-timesyncd[733]: Contacted time server 185.125.190.57:123 (ntp.ubuntu.com).
Dec 08 23:17:51 Mint-Yoga systemd[1]: apt-daily.service - Daily apt download activities was skipped because of an unmet condition check (ConditionACPower=true).
Dec 08 23:18:09 Mint-Yoga systemd[1]: systemd-hostnamed.service: Deactivated successfully.
Something is actually preventing the system from being locked at all. If I click the lock icon in the menu above the log out button, nothing happens.
You would think so, wouldn't you? But no, it lets me pick right back up where I left off without a password prompt. I thought maybe I had forgotten to set a password altogether, but I hadn't.
That is false.
Sometimes they were both.
If it walks like a duck and quacks like a duck, it might not be your son.
because it's auto-pay only
It's true, believe me. Many people are saying it.

We ran out.