Hi,
When I do who -b; uptime I get
system boot 2021-10-12 17:05 16:36:09 up 30 min, 1 user, load average: 0.00, 0.00, 0.00
As you can see the boot time reported by the last command is ahead. I have noted it is one hour ahead after a reboot.
I have checked the system time in the BIOS before booting Linux and it is correct.
I don't know how exactly it comes but I guess it has something to do with local vs. system time. You have UTC as timezone but because of DST it's one hour apart.
What does last report?
On my test system I find the reboot which is shown in the who -b output in the last output, and the uptime reported by last again matches with the uptime output.
Regards, Simon