Berman-era Trek might have been targeting a different demographic than other shows of its time.
TNG targeted a Family Audience. It was also targeting Baby Boomers and Generation X at the same time since Generation X was such a smaller generation. Which means that TNG could only go as controversial as Boomers were comfortable with and what they were comfortable with what their kids would see. If TNG were targeted towards Generation X and Generation X alone, it would've been very different.
DS9, VOY, and ENT tried to hold on to TNG's Audience, but was losing them. Eventually, after the fourth season, Ira Steven Behr on DS9 stopped caring and figured fans were either with them or they weren't, but on VOY and ENT, getting the TNG Audience back was something they were always obsessed with, so they didn't really shift.
DSC and PIC on the other hand, seem like they're targeted squarely at Generation X and Older Millennials. I'm dead-center their target audience. And we grew up differently than Baby Boomers did, who they're not trying to appeal to anymore. That's why they felt more at liberty to have LGBT Representation, have more profanity, be more feminist-leaning, etc. That's why they finally decided they could change the look of the TOS Era. The people who were mainly fans of TOS have aged out of the demographic they're trying to reach.
Generally speaking. I think DSC was initially in the TOS Era because CBS had to be Prime Timeline, but they also wanted to ride off the momentum of the Kelvin Films. How the TNG Era looked during the TNG Era was left unchanged by PIC, because they don't want to piss off their target audience who grew up with it and they still see as marketable.