macos terminal - df shows wrong disk capacity

I'm using terminal under Sonoma 14.1.2 on a Macbook Air M1.

I only have the main 2Tb hard drive.

When I use terminal, I get this:

$ df -H /
Filesystem        Size    Used   Avail Capacity iused ifree %iused  Mounted on
/dev/disk3s1s1   1995G   9897M   1065G     1%    390k  4.3G    0%   /

To try to fix this, I went to the recovery system and ran Disk Utility. I used the same command in terminal on the recovery system. It gave:

$ df -H /
Filesystem        Size    Used   Avail Capacity iused ifree %iused  Mounted on
/dev/disk3s1s1   1995G   9897M   1065G     95%    390k  4.3G    0%   /

When I booted back to the live system, it was, again, giving the wrong capacity at 1%.

Does anybody have an idea of what is going wrong?