Usually utility player can field a position or two at or above replacement level defensively, or they can hit well enough to PH for weaker hitters on the team.
Holt does not really do either of those two things. His ability to play 8 positions is his only true valuable commodity, despite not being to play any very well.
Now that we have a DH who can play another position, that need for an 8 position utility player has diminished to some extent.
Think of it this way, is there any position on our depth chart where you think Holt is good enough to be the number one sub, either short term or long term? To me, he's a "utility player" with very little utility.
Here's my choice on our positional depth chart (AAA players maybe used in case of injury in parenthesis):
1B: HRam/Moreland-- Swihart (Travis long term) then Holt (Thoughts of using JD or Devers at 1B makes some sense.)
2B: Pedey-- Nunez, Hernandez, Lin/Marrero then Holt
3B: Devers-- Nunez, Hernandez, Marrero/Lin then Holt
SS: Bogaerts-- Nunez, Hernandez, Lin/Marrero then Holt
OF: (Beni & Betts can be shifted around to allow the sub to play LF in Fenway and RF away)
Beni, JBJ, Betts-- JD, Swihart, Moreland then Holt
When Holt was an all star, he was clearly our best sub at several positions, and we had a DH who only played DH (1B rarely in NL parks). Now, he's not.