With ventoy, you don’t need to format the disk over and over, you just need to copy the ISO files to the USB drive and boot them directly.
Whats ventoy? Ventoy is a free and open-source utility used for writing image files such as .iso, .wim, .img, .vhd(x), and .efi files onto storage media to create bootable USB flash drives. Once Ventoy is installed onto a USB drive, there is no need to reformat the disk to update it with new installation files; it is enough to copy the .
For some reason, it didn’t work on OpenBSD. I couldn’t install the file sets until I wrote the image to the flash drive normally.