SSD partitioning in Windows 11

I have a 256GB SSD on my laptop with Windows 11 OS. It is divided into two drives:
Windows C: (142GB of 220GB free) and Recovery D: (1.8GB of 16.4GB free).

I would like to create a new partition on the Windows C: drive, for example with 80GB. To do this, I use “Disk Management”, “Shrink Volume” and get the following screen: As you can see here, in the “ Shrink drive C: ” window, “ the space to be shrunk in MB” is specified as 875MB . So not even 1GB. There is 142GB of free space on the Windows C: drive. My question: Why is the space to be shrunk limited to 875 MB and how can I create a partition of 80GB please? Thank you in advance for your help.