Here is a copy of the output from diskutil; I can't seem to expand any of the containers, partitions, etc.

diskutil list
/dev/disk0 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: *214.7 GB disk0

/dev/disk1 (external, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *214.7 GB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_APFS Container disk3 32.0 GB disk1s2

/dev/disk2 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *121.3 GB disk2

/dev/disk3 (synthesized):
#: TYPE NAME SIZE IDENTIFIER
0: APFS Container Scheme - +32.0 GB disk3
Physical Store disk1s2
1: APFS Volume Macintosh HD - Data 6.1 GB disk3s1
2: APFS Volume Preboot 79.3 MB disk3s2
3: APFS Volume Recovery 529.0 MB disk3s3
4: APFS Volume VM 2.1 GB disk3s4
5: APFS Volume Macintosh HD 11.0 GB disk3s5

Thank you for reaching out. Once you have increased the size of the EBS volume on your Mac1 instance, you can execute following commands within macOS guest to increase the size of your APFS container.

Copy and paste the first three lines

PDISK=$(diskutil list physical external | head -n1 | cut -d" " -f1)
APFSCONT=$(diskutil list physical external | grep "Apple_APFS" | tr -s " " | cut -d" " -f8)
sudo diskutil repairDisk $PDISK

Accept the prompt with "y", then paste this command

sudo diskutil apfs resizeContainer $APFSCONT 0

Since the EBS volume was resized after boot, an instance reboot is required before the additional disk size is available for your use.

We are also updating our documentation to reflect this use-case and appreciate your feedback here.

Thank you SO much; this worked great!

It´s interesting that you have to update the documentation only after customers ask for "this usecase". The usecase of using XCode to develop iOS apps is the main use case you are advertising on your website! Now many users are fiddling around with this trying to make it work and wasting money because they trusted the advertisement on the website.

It seems like this has still not been added to the docs anywhere, I had to search the forums for it.