Discovery is just written by toddlers or something.
Like, I was willing to blame it on continuity baggage for the first 2 seasons, plus the first season of every Star Trek is lackluster so whatever. But in season 3 it looked like they'd finally hired a competent writer for a few episodes, Osyraa was suddenly a more nuanced character, the Federation was offered a path to its goals that meant they'd have to compromise their ideals, Burnam was becoming Han Solo [0], Tilly was being slotted into the leadership role her character is actually good at, etc. Then at the last second the toddlers took over again, Deus-ex Burnam'd[1] the ethical decisions, shoved Tilly back into a science role, put Suru on a bus, and put Han Solo in charge of a starship for some reason. What the hell!?
[0] Which is what her character should be, clearly. She doesn't follow rules, she doesn't work well with others, can't lead worth a damn, and she readily compromises her ethics to achieve her goals. She's a terrible Star Fleet captain but she'd be a great chaotic-good rogue.
[1] What the fuck is with Marry-Sue God-Queen Burnam anyway? She has like 95% of the screen time or something and her Picard speeches inspire nothing but contempt for the writers. Like, answer me this: There are regular characters on the bridge other than Tilly, Burnam, and Suru. What are their names? There's Detmer, who we kinda know about because she had that PTSD episode on screen, and I guess that one woman is a cliff diver or something, but I don't know her name. And dude in the back who got horribly murdered by Mud that one time? These aren't red shirts, why aren't we getting any character development for them?
Alright, sorry, I went on a bit of a rant there.
P.S. I'm hesitant to blame the actors for bad performances. I feel like there's a lot of bad direction and obviously terrible material to work with.
P.P.S. I actually think the hack writers are are a pretty good fit for the mirror-universe stuff. It's still garbage writing, but it just sorta fits that place.