Conditional formatting - color gradient based on another cell's value

Hi All,

I'm struggling with a problem and hoping one of you can help me.

I'm organizing an event and I have a big tasklist in excel of things that have to be done by a certain duedate.
This original file was horribly outdated and a mess.. BUT it's functions and formulas were working.

I had to change the "look" of the file.. bot for some reason I can't get the conditional formatting on the due dates to work.

Explanation:

CELL A1 is the due date.
CELL B1 is the state. (OK, NOOK, BUSY, NA)
The event date is set to 2022-11-24

The date in CELL A1 is based on a little formula that we decided on by which date each task has to be completed on. (basically event date minus X days)

GOAL:

Whenever a state in CELL B1 is "BUSY" or "NOOK" we want to apply a gradient color on the CELL A1. based on how close we are on the due date.
(10 days before the due date it starts getting slightly yellow and more orange towards the due date, and when it passes the due date it should go towards red)
When the state in CELL B1 is "OK" or "NA" nothing should happen.

Any help would be MUCH appreciated.. I have been trying to fix this for days.. tried workarounds found on google.. but never could find the exact fix to my problem.

Thanks in advance!

Edit: added a test/sample file.