However, the old 16-bit check box bug IS back! DO NOT set an Epson whose Mac print driver has such an option to be on. It doesn't do jack and worse, it prints awful. Otherwise, everything is fine and matches my output from older Mac OSs.
Just to add information/confusion ---
Short story: I found the 16 bit bug when printing from Photoshop, but not when printing from Lightroom Classic.
Long Saga: With a brand new MacStudio Ultra and Studio Display and a freshly calibrated Spectravision P271Q, I decided to fire up an old Epson 4880 which had not been used for a couple of years and cleared out its clogs (one power cycle) and checked head alignment. Then printed a set of tests with Lightroom Classic on my last roll of Ilford GFS with the Ilford profile at my usual settings, 16 bit, 2880, etc. There was a decided green cast (correction needed of ~15M in old color darkroom terms) compared to the calibrated soft proof screens AND an old print from the same file (which agreed sufficiently with the screens). So something changed. I had been sure to put in new Magenta & Light Magenta cartridges.
So I went through numerous tests including full nozzle checks and changing every parameter I could think of including 16 bit on and off, and printing from an old Intel based iMac and the new Apple Silicon on the latest beta of Monterey and the latest Epson driver. Nothing made any difference to the green(ish) cast. All this on LR Classic.
So, I switched to Photoshop, same settings (16 bit on) and a really horrible dense, dark, shadows blocked up mess came out. After another day (and with my Ilford GFS running out) I started making test strips on manually fed ends of the roll, and switched off 16 bit. That got me back to the new normal with the greenish cast (still printing with Photoshop).
I will wait until B&H delivers the new Ilford Gold Fibre Gloss on Monday which I will try as a replacement for Gold Fibre Silk to see whether the greenish cast persists. Ilford support sent me a profile for GFG which they have not yet put up on their website.
For clarity, I switched of 16 bit both in the application(s) dialog and in the Epson print driver dialog. I presume the application switch determines whether 16 bit is sent to the printer, and print driver switch determines whether the printer will use 16 bits if it gets it [?]