After trying multiple times using the Macbook air ports. I tried a different setup. Used an external USB/USB C dock (Dell Universal Dock D6000) with a USB C to USB C cable connected to the phone.
So Macbook Air (2013) -> Dell Universal Dock -> Pixel 2 XL.
And when trying the script it finally worked!
~/Desktop/ubports/halium-install$ ./halium-install-standalone.sh -p ut -s ubuntu-touch-android9-arm64.tar.gz system.img
[sudo] password for :
D: Chosen rootfs is ubuntu-touch-android9-arm64.tar.gz
D: Chosen android image is system.img
D: Chosen release is ut
D: Compress images before pushing: false
I: Writing rootfs into mountable image
I: Writing android image into mountable image
I: Running post installation tasks
enabling SSH ... [done]
Please enter a new password for the user 'phablet':
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
I: Shrinking images
e2fsck 1.45.5 (07-Jan-2020)
resize2fs 1.45.5 (07-Jan-2020)
Resizing the filesystem on .halium-install-imgs.Yy132/system.img to 231448 (4k) blocks.
Begin pass 3 (max = 20)
Scanning inode table XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on .halium-install-imgs.Yy132/system.img is now 231448 (4k) blocks long.
I: Unmounting images
I: Pushing rootfs and android image to /data via ADB
I: Pushing rootfs to /data via ADB
.halium-install-imgs.Yy132/rootfs.img:....0 MB/s (3221225472 bytes in 109.898s)
I: Pushing android image to /data via ADB
.halium-install-imgs.Yy132/system.img:...27.5 MB/s (948011008 bytes in 32.918s)
I: Renaming to system-as-root compatible system image
real 2m22.986s
user 0m0.438s
sys 0m6.972s
I: Cleaning up
umount: .halium-install-rootfs.5pR4w: not mounted.
Now on to testing capabilities. Thanks for all your help and input. @Flohack recommendation to try different host ports helped!