Made a boot USB for Absolute with dd and unetbootin but no USB option on boot

I downloaded Absolute's most recent .iso file. I tried using dd (via antiX Live-USB-maker in dd mode) but when I try to boot it, and press F12, the USB drive doesn't appear.

I tried using unetbootin ver 702 to burn it, and got the same result.

I added it to a ventoy drive I had created, and it does boot, but can't run the install because it says it couldn't find the software in the slackware directory.

I also tried using Balena Etcher to burn the USB and it gave a warning saying the .iso is missing a partition table and probably isn't bootable.

I can't ask on the absolute forum because there is no option there to register for the forum.

I know its a slackware derivative, and so I tried using iso2usb.sh to write the iso to usb, but it gives me an error about invalid blocks

I'm stumped... Can anyone help, please?

Code:root@Dell-I7:/home/thriftee/bin
# ./iso2usb.sh -i /media/root/BIGData/iso/absolute64-20240602.iso -o /dev/sdc
#
# We are going to format this device (erase all data) - '/dev/sdc':
# ---------------------------------------------------------------------------
# Vendor : USB
# Model : SanDisk 3.2Gen1
# Size : 14688 MB
# ---------------------------------------------------------------------------
#
# FDISK OUTPUT:
# GPT fdisk (gdisk) version 1.0.9
#
# Partition table scan:
# MBR: MBR only
# BSD: not present
# APM: not present
# GPT: not present
#
#
# ***************************************************************
# Found invalid GPT and valid MBR; converting MBR to GPT format
# in memory.
# ***************************************************************
#
# Disk /dev/sdc: 30081024 sectors, 14.3 GiB
# Model: SanDisk 3.2Gen1
# Sector size (logical/physical): 512/512 bytes
# Disk identifier (GUID): 37FF2688-0D96-45AE-AA45-DD74505794B1
# Partition table holds up to 128 entries
# Main partition table begins at sector 2 and ends at sector 33
# First usable sector is 34, last usable sector is 30080990
# Partitions will be aligned on 2048-sector boundaries
# Total free space is 30080957 sectors (14.3 GiB)
#
# Number Start (sector) End (sector) Size Code Name

*** ***
*** If this is the wrong drive, then press CONTROL-C now! ***
*** ***

Or press ENTER to continue:
1+0 records in
1+0 records out
512 bytes copied, 0.12101 s, 4.2 kB/s
Creating new GPT entries in memory.
The operation has completed successfully.
The operation has completed successfully.
The operation has completed successfully.
Disk /dev/sdc: 30081024 sectors, 14.3 GiB
Model: SanDisk 3.2Gen1
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 0DD53B31-F8BE-4BD4-8115-2CBFA4B41D7C
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 30080990
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number Start (sector) End (sector) Size Code Name
1 2048 4095 1024.0 KiB EF02 BIOS Boot Partition
2 4096 208895 100.0 MiB EF00 EFI System Partition
3 208896 30080990 14.2 GiB 8300 Slackware Linux
3:2:1 (legacy BIOS bootable)
mkfs.fat 4.2 (2021-01-31)
mkfs.fat 4.2 (2021-01-31)
mke2fs 1.47.0 (5-Feb-2023)
mkfs.ext4: invalid blocks '/dev/sdc3' on device 'Install'
root@Dell-I7:/home/thriftee/bin