they'll be back in a few months
AT&T will probably drop the '5G E' bullshit for now. In a few months, they'll be back at it with something like '5G X'. 'X' as in 'eXtensible'.
Which will, of course, still be 4G/LTE. And if you use your imagination, it could be eXtended to 5G. Some day. But hey, they just bought themselves a few more years of bullshit.