Beginner Question About Starting Fresh and Spending That Must Happen Before Payday

I simply can't wrap my head around a probably very beginner problem.

I have all of my transactions linked to by bank accounts and my credit cards to ynab. I mostly use credit cards to make everyday payments.

My issue, I'm trying to look at one month at a time, an example:

Day 1: Mortgage ($2000)

Day 2-13: Food/Childcare/etc ($1000)

Day 14: Payday $2500

Based on what I'm reading about ynab, I technically shouldn't be able to pay my Mortgage because it comes out before I'm paid. However, if I just start assigning money I don't have to pay the Mortgage then I'll be negative assigned, which I've read people saying it's wrong. If I just wait until Day 14 to then assign money, I feel like I'm not using ynab correctly and i don't feel tethered to a budget it's just a spending tracker.

I've looked around and I haven't seen people talk about this specific issue (or, at least in a way that resonated with me) and I just need some help because I'm probably over thinking it. I would appreciate people's advice when starting completely fresh.

I do have a savings but I want to use ynab to build up that savings and buffer for one off expenses that pop up throughout the year.