considering PopOS is trying to tackle Ubuntu they really need their dual-boot setup to be a lot less tedious

Instead of resizing Windows efi partition, I created a new one for pop os as well. So now my system has two different efi partitions. No chance of any messing up.

I tried it but the tool wouldn't let me resize the EFI partition

If would recommend you create a bootable Windows 10 USB from the MS website and reinstall the PC with a clean Windows installation so you have the same Windows installation as shown in the video. Also, you'll be a lot happier with all the bloatware removed.

Press Shift+F10 while installing Windows to open a Command Prompt window.