This was just last week. I did the same test a couple of times: 100% certain no swap subvolume is created. It is either a file on / or a partition.
I simply select wipe disk, select swap type and FS type.
I have not used manual partitioning.
For now, I simply select “no swap” and “BTRFS”.
After installation, I run the script (that I updated) from this topic:
This will calculate the amount of swap needed for hibernation, create a subvolume and create the swapfile, turn on swap and perform necessary tasks for hibernation to work.