My solution for Part 1(also in sheets—I wonder if there are any more of us?) was basically the same, but it's cool how all three of us solved Part 2 in slightly in different ways.

Personally, I converted the "view" of trees in each direction (using OFFSET) to a binary string based on if they were higher or not, and then used REGEXEXTRACT to get the subset of that the tree in question could see, and then took the LEN of that and multiplied.

Here's the spreadsheet, by the way: https://docs.google.com/spreadsheets/d/1n\_mYcvJpaMuyONgmuoq6ubT1MrDdAcHahA3eTUkPtuI/edit?usp=sharing