No, unfortunately that is not possible, there is no possibility to expand the memory. I looked to see which devices also have 256 GB of memory. These devices from Poco would have 256 GB of memory and can be expanded up to 1TB with a MicroSD card:

Xiaomi Poco M4 Pro (256 GB, Power Black, 6.43 ", Dual SIM, 64 Mpx, 4G)

Xiaomi Poco X3 Pro (256 GB, Frost Blue, 6.67 ", Hybrid Dual SIM, 48 Mpx, 4G)

One from Samsung would also have 256GB and a micro SD memory expansion:

Samsung Galaxy A52 EU (256GB, Black, 6.40 ", Dual SIM, 64 Mpx, 4G)

And this Oppo Reno 2 could also be expanded:

OPPO Reno2 (256 GB, Ocean Blue, 6.50 ", Hybrid Dual SIM, 48 Mpx, 4G)