I mean, I get that Bryce is sort of an extreme example in that she's directed basically nothing, couple of shorts aside, but that's kind of a flawed argument in a macro sense.
The Russos had never handled a budget, resources of scale, or really done anything in the way of action pre-The Winter Soldier. Coogler was arguably a gamble pre-Creed. Hell, Favreau himself for Iron Man, he wasn't exactly a proven quantity on that level of project at the time. Yes, they had more of a resume going for them than Bryce, but it's the same concept.
I think you'd be right if it were more like an original property, a studio taking a gamble on someone like Bryce and throwing them an action-heavy blockbuster movie or big expensive Game Of Thrones type episode out of nowhere, but it's a little different with Lucasfilm & the Disney machine I'd imagine. Someone else has likely written the thing, it's all been vetted quality-wise and maybe even storyboarded out before she even comes aboard. You've got a (now) experienced guy like Favreau godfathering it all, probably right there on-set, Kennedy & Co too. If she has any questions, or if it's not looking to be turning out well while actually in production, there are plenty of people to steer her back on course and guide her through it.
And even that sounds a little harsh on Bryce herself, assuming she needs the hand-holding. Yeah, we haven't seen anything she's done, but that's not necessarily reason to doubt her either. Again, you've gotta start somewhere, and on a project by a studio and Hollywood team her dad's run with going back decades is as good a spot as any. I don't think anyone's necessarily saying she has inherited her dad's chops, but there's just not really cause to write her off either. It's an episode of a TV show, not some huge financial gamble. Plenty of actual TV show showrunners have never directed anything major before (hell, look at Whedon on Buffy, Abrams on Felicity then Alias), let alone people doing one episode (that we know of). She'll be fine, especially with Favreau hanging around.
EDIT: As for your Kinberg example, Dark Phoenix looks awesome. He co-wrote Days Of Future Past too, people love to cite Apocalypse while omitting the former. I'm not worried in the slightest about that flick.