Trouble getting a read with smartphones

Possibly, coupling is really important.

Using the same orientation you found with the xFD, can you use your phone and press down “hard” and try to read with TagInfo

Me too

Also, what are you trying to do with your xSIID? What is your end goal?
business card?
Rick Rolling?
Smuggling less than 2kB of data across international borders to sell to foreign intelligence agencies etc?