Yes. Erasing a device gives you the option to change the partition table type, as well as create/format volumes.
Erasing a volume doesn’t let you change the partition table type, because the partition table doesn’t exist at that layer of the file system structures.
And you can’t create an APFS container if the partition type is not GPT. I believe flash drives smaller than 2TB usually come pre-formatted using an MBR partition table, for maximum compatibility with older system software.
Yes, because of what I learned here on TidBITS (quite likely from you, thank you).
However, I can eject my SSD and it and its volumes still appear in Disk Utility until I disconnect it, and I can re-mount any volume. I assume this difference between what I see and what you described is because I’m using an SSD and this thread began with a discussion of a flash drive.
Interesting. What’s the interface? All of my devices are USB. Perhaps Thunderbolt devices behave differently.
When you eject a USB device, I think it is deleted from the underlying device-tree that manages all connected USB devices. But Thunderbolt devices are (effectively) PCIe devices, which follow a completely different connection paradigm.
Short answer: Thunderbolt.
I had no idea; I thought it was USB. However, I got a System Report and it says my MacBook Air (M1, 2020) has two Thunderbolt ports, and I was using one of the two ports.