Laptop uptime - since suspend

Just been supporting someone remotely and was waiting for them to turn on their laptop...

Whilst troubleshooting I ran uptime to see how long we'd been working on the problem and saw it was up for ~2 weeks...

Which made me think ... how do you tell how long a device (laptop) has been running, but since it's last suspend / hibernation?

I can find it from other clues such as journalctl -b -fu systemd-logind and look for Lid opened, but I was really looking for an smarter way...

Just a nice little challenge for anyone bored at this time of year :)