Only official builds are integrated in the graphical installer, you can see this chart for official builds: iodéOS official supported devices - iodé
Unofficial builds need to be bootloader unlocked and have a fully functional LineageOS port and kernel source, firmware blobs, etc available. But the Samsung Galaxy Tab A 8.0 (2019) doesn’t have those available. I was actually just looking in the last few days too since I have access to one of those.
I may try the GSI build for it when I get some time.