Is this Samsung Galaxy A01 5G capable?

No, The Samsung Galaxy A01 – AT&T PREPAID does not support 5G networks.

AT&T Galaxy A01 will work with 4G LTE and other networks below that.

Samsung Galaxy A01 – AT&T PREPAID Wireless Technology

4G LTEBands 2, 4, 5, 12, 14
4GHSPA+
3G – UMTS750/850/1900MHz
GSM/GPRS/EDGE850/900/1800/1900MHz