According to above post thread, UFS2.1 for A7Z, maybe it cheaper than 3.1 UFS part number on RADXA schematic, but need edit PCB.
I found some second hand UFS on Taobao. For new chip, price is more than A7Z.
if you can create an Taobao account, you can try to order and send it to third party transport service at your local to delivery. Or, the third party service can help you to order on Taobao and transfer to you.
link on lcsc for ufs
lcsc.com also help to order for samsung ufs. You can order on lcsc and transfer to third party service to delivery.
link on lcsc for ram.
need check RAM datasheet before order RAM on lcsc.
make sure do not put order from digikey or mouser on lcsc, they need custom fee. only link on lcsc store or no custom fee at your side destination location.