There's a feature to allow charging from USB ports while a computer is off, Lenovo calls it "Always on USB." That feature is constantly using power even when nothing is plugged in. To test if any ports have that feature power off the computer then try plugging in a simple 5v 500ma usb device to charge. If it starts charging then it has that feature and will drain power. If no options to disable in BIOS then as far as I know stuck :(
I've worked on a couple recent gen refurb laptops (dell and lenovo) with that feature but lacking any disable option in BIOS. I've tried to get into the habit of plugging in whenever not being used but still end up with things empty more often than I like. Very frustrating and I think only hope is future bios update to give that option.
You can try seeing if you can set the speed/duplex of NIC/ports manually if auto-detection keeps getting it wrong.
Unifi I like the APs for mesh & multiple SSID+vlans but I keep them on dedicated vlan with zero internet access because I don't trust that I properly followed instructions to disable opted in analytics/telemetry. The mgmt software is alright but new UI wastes a lot of space. The PoE switch was alright until it stopped being able to keep a config last year. USG router I kept less than a year because it was too slow with any useful features enabled. I've glanced around at replacement APs here & there but pretty much waiting until I have more wifi 7 compatible devices and that'll be another couple years.