tomek123:
Unfortunately, the maximal sleep time is 2h.
Why is that a problem ?
Put the Arduino to sleep, with watchdog timer off and set to wakup on interrupt.
When it wakes up increment a counter, and go back to sleep.
When at wakeup the counter has reached however number of 2 hours you want, then do something.
The TPL5110 has an active current of 35nA, not 20uA.