Hello and welcome to the Monday community!
There are lots of different ways to accomplish this but based on your use case, here is the simplest way I can think of:
Status Column = Priority Levels
Date Column = Deadline Date
When date arrives and at status is something change it to something else
You will want to set up 2-3 automations like this for your priority levels. For example, here is one that sets the priority level when only 1 day is left before the deadline:
The “1 day before” can be changed however you need, so if you want to set High to 3 days before, Medium to 6 days before etc. Its fully customizable.
I said 2-3 automations, because you could just set every new item to be default Low Priority and then only have the priority change once the date gets closer.
Hope this helps!