Are you referring to the chip at the center of the photo? That looks like a small flash / EEPROM chip in a 4-pin WLCSP package. These come in a number of different physical and storage sizes, but [link|https://www.digikey.com/en/products/detail/stmicroelectronics/M24C08-FCT6TP-T/4959846|here's one example|new_window=true]. If you can precisely measure the package size and BGA pitch you could narrow it down further. Being buried under glue suggests that the designers want to protect the contents of the chip / prevent tamper, which lends further to it likely being a memory device.