I think that will never be a 64" version of P9570. According to the product line history, new 64" printer is on the next generation.
7800 / 9800
7880 / 9880 / 11880 --> no change on 24"/44" hardware, a little change on ink (Magenta), 64" model use new head
7900 / 9900 --> massive change on hardware, add new ink (Orange/Green), use previous 64" head, no new 64" model
P7000 / P9000 / P20000 --> no change on 24"/44" hardware, a little change on ink (Black/Yellow), 64" model use new head
P7570 / P9570 --> massive change on hardware, add new ink (Violet), use previous 64" head, no new 64" model
Maybe P9000/P10000 models is a market test, to find out people wants vivid color or high production volume. P9000 can choose OGV set of inks for wide gamut. P10000 has smaller gamut but high volume. It is a confusion time, but if we ignore P9000's Violet option and P10000 model, things are all going on the track, except P20000 has no OG inks.
I guess the Epson next generation printers would be like that:
P7XXX / P9XXX / P2XXXX --> 24"/44" have the same hardware with P7570/P9570, a little change on ink (maybe Cyan), 64" model use new head (maybe 1200 nozzles/channel)
But it will be in the long future since we are facing economic crisis because COVID-19.