I posted a link to my spreadsheet in a thread response a few weeks ago. It's now been updated and enhanced.
I created a google spreadsheet for AP calculations and other things. It now has all of Phase 1, 2, and 3. It calculates how much AP it will cost for certain advancements. There is one column for you to enter your current advancements and another for desired advancements. Finally, there's a place for you to enter how much AP you have to spend. As you enter values for planned advancements, It will automatically update to tell you how much more you would have left to spend. Make a copy for yourself in order to fill in the values. I have the Phase 4 information but won't release it until I've unlocked Phase 4 (it is considered a spoiler). https://docs.google.com/spreadsheets/d/1F5ejYV2bYeaP6yTH683A27iTY8ulDFxGXjwh0zXB82s/edit#gid=1446462419
It comes pre-loaded with a plan to spend 1009 AP. The AP amount available to spend is preset to the amount of AP you would gain from beating all levels exactly once (with no AP boosts). By filling in values for the Update Qty field (and leaving the Current field blank), you can quickly plan how to spend your AP for the first playthrough of all levels.
It also contains a sheet for mines, dig sites (some are not verified to exist), artifacts, and tips (Q/A). The Q/A tab has recommendations for artifacts, multi-level play, and how to spend AP. There is a link to a strategy guide (close to complete) that I've been working on for a while, which contains more detailed advice. The level AP sheet has values that are off by a very small amount, due to rounding error.
The documents will continue to be updated. The spreadsheet contains a link to itself on the AP tab, allowing you to return to my latest version from your downloaded copy to check for changes. You will need to create a new copy of the AP sheet in order to incorporate any new updates. I may also fine tune the AP spending suggestions with new recommendations on how far to update Mercs/Army Camps before beginning Phase 3.
Edit: Just fixed a small bug
Edited 4/10/2021 19:43:16