Also, I think there's a bit of a difference here. In "Relics" they hired the original actor who played the original character, so when he went on the holodeck wanting to look at his original ship, it made sense that they'd design it to be the same.
No, it doesn't. TMP had the same actors as TOS, and they still redesigned everything. Heck, TNG redesigned Worf's actual forehead between season 1 & 2. So it doesn't have a thing to do with who the actors are. As I've already explained, they had to use the same design for budgetary reasons. They couldn't afford to build a whole bridge set, so they had to fake it using stock footage and rented fan reconstructions. They didn't have the option to do it any other way.
What a lot of laypeople tend to forget is that making this stuff is expensive. Most of the time, the fundamental reason why a decision was made is going to come down to money rather than pure creativity.
However I wish there be a bit more consistency. I noted earlier I thought Enterprise did a pretty good job with the set design striking a balance between making it less advanced then the NCC-1701, but still look futuristic from our standpoint. It seemed at least to me with Discovery that they abandoned any attempt to strike that balance.
I will never understand why anyone is surprised that completely different creative teams have made different creative decisions. Or that a show that was meant to relaunch a dormant franchise has actually relaunched it, taken a new and fresh approach rather than just perpetuating what the previous generation did. People just got spoiled by having a single continuous incarnation of Trek produced by the same people for 18 years. They came to think that kind of uniformity was the norm rather than an exception.