Ahh… I have a lot of Battery Budget Calc’s for the Boron LTE scattered around this forum, as do others. This post has a quick and dirty example for a similar battery (19 aH, publishing every 2 hours).
But I don’t have Boron test results with the latest firmware.
Do you want the ATTIny to wake up and keep count for 24 hours, then only wake the Boron up once a day ?
I’d lean towards only a Boron, using manual mode.
The Boron can quickly decide to just increment the counter and return to sleep if it’s not time to power-up the cell modem and perform the cloud publish.