Both of those are your problems, I had the same pair on battery water meter tags last year.
Current: the UART peripheral being enabled keeps the HF clock up, that alone is hundreds of uA when active and tens when idle. Set CONFIG_SERIAL=n and CONFIG_LOG=n in the release build (or CONFIG_PM_DEVICE and suspend the UART). Also enable the DC/DC (CONFIG_BOARD_ENABLE_DCDC=y, needs the inductor fitted on your board), and make sure unused GPIOs aren’t floating. That got us from about 35 uA to 3.
Online status: for child devices Hermetry takes the online state from the gateway’s v1/gw/connect and v1/gw/disconnect messages, so your gateway is telling it the tags are gone. With 60 s advertising and a 60 s timeout, one missed advert means a disconnect. Make the gateway wait for 5 missed adverts before sending disconnect.
For the alarm, set the Device offline rule’s Open after to something like 900 seconds so a short gap doesn’t page anyone. More on how child status works: Gateways and devices behind a gateway.