Red is confirmed:
New scene from the trailer for 3x06 “Scavengers” in a Starfleet command centre or operations room has lots of officers wearing the standard grey jacket uniforms with a red stripe down the front:
Interestingly, quite a few of these look like they might have both gold edging to the red stripe and also black shoulder straps, although worn front-to-back across the shoulders rather then along the shoulder like epaulettes. The look is reminiscent of the shoulder straps on some of the TMP uniforms and also the shoulder straps on the TWOK maroon jackets.
Best guess: this is the more usual "admiral" variant of the standard uniform and the version worn by Oded Fehr's character is more of a one-off uniform for the Commander in Chief.
It could be that they have added gold edging to the red for Captains, in the same was as they have used the additional gold on the shoulders of the original
Discovery uniforms. Again, best guess:
Gold down
one edge of the red and NO shoulder straps, just four pips on the transporter badge
= captain
Gold down
both sides of the red PLUS shoulder straps
= admiral (with specific grade shown on the shoulder straps)
It'll be interesting to see if this turns out to be the case.