Unable to turn off printer colour management

[Abraxas2000]

I am printing on an Epson PRO 3800 with Photoshop CC 2019 on an iMac running High Sierra 10.13.4.

The problem: I want to use a specific paper profile, and print under  "Photoshop Manages Colours". However, when I select this option in the Color Management panel on the right, I get a triangular alert symbol and the reminder "Remember to disable the printer's color management in the print settings dialog box". When I then go to Print Settings>Color Matching, "ColorSync" is marked selected, but both choices are greyed out. In the Print Settings>Basic panel, both the "Color" dropdown menu choices and the "Color Settings" dropdown menu choices are greyed out. In other words, it doesn't look as though I can actually disable printer colour management at all.

An Adobe assistant I consulted ending up saying, rather unconvincingly, that it shouldn't make any difference, but that has to be flat wrong; I confirmed this by making a test print which was way off.

Any help very gratefully received.

[Abraxas2000]

Thanks to all, and particularly to Alan.

[owl bits]

Happy to help Abraxas2000! Keep asking if you need further info.

All best with your printing. Hope you get more consistent results soon.