Extremely Slow Macros

I am a complete novice when it comes to VBA. In fact, I am completely self-taught in Excel, which means I tend to do things via recorded macros when I can and as soon as I find something that works for my issue, I stick to that.

A little about the file: I work in manufacturing and have created my own file to calculate machine load and capacity. The original file works alright. Then I made a second file which is inspired by the first, but has more options to it.

The original file only calculated by annual volume for 4 years from one source of volume data. (300 tools across 32 machines)

This new file can have one of two volume sources (Projected or Customer Given) and shows 8 years of data, either annually or quarterly. This one has a quarterly load and heat map, as well. (Also 300 tools across 32 machines)

I have code that works in the new file, but it runs insanely slowly. My guess is that is because all my macros, graphs and calculations interract with multiple sheets.

In the attached file, I scaled a lot of things down so that I can upload:
Program codes from 25 down to 4
Quarters & Years from 2021-28 down to 2023-25
Machines from 32 down to 4

That sped it up a TON, so I think the problem may be my massive quantity of data... So here is the question: Is there something I can do with my macros, given the stupid way I set this up because I don't know VBA (or really any appropriate Excel methods), that will help speed this up when I go back to 8 years and 300 tools? Or am I just out of luck because this comes out to several thousand data points?

Thanks!

I'd note that there are links into another workbook. If that workbook were closed and there were lots of formulas referring to ranges in it, that sort of thing can slow Excel to a crawl.