So, time travel. It's tricky to write! Seen it done quite badly, in fact. Gets messy super quick, which sucks for your plot but REALLY sucks for your characterization. Tesh actually does a pretty good job here, though. She keeps it clean, clearly delineated, and as linear as she can. I like what I guess you would call 'Groundhog Day' type time travel stories: stories where a person goes through iterations of the same events, changing things around them and then changing themselves as those changes stack up. And this is a strong example!
I made the mistake of checking out the Goodreads reviews after I finished reading. The first page of reviews were significantly harsher than I expected, because I thought this book was very fun. Not perfect, I guess, but a lot of folks are hating it not for what it is but for what it isn't. Which, you know, I've written that review too a few times, but it's not a very useful critique. There are a lot of other books in this world that SOME DESPERATE GLORY isn't, but it is itself. And itself is quite good! My suggestion is that readers should ignore the BookTok-style Discourse and just read the the book.
SOME DESPERATE GLORY is dramatic, action-packed, twisty and turny, with lots of moments of introspection. People are learning from their mistakes all over this story. There are certainly a lot of complications that happen on various storytelling levels (the world resets! three timelines! the protagonist becomes a mostly different person with a different history about halfway through!), but it tends more toward space opera than hard sf. There's a romance subplot for the protagonist that is subtle and underdeveloped, but I have a lot of hope for norm-breaking exo-romance in a sequel. And I love everything about breaking free of indoctrination and leaving the cult but still having the substance of your indoctrination within you.
n.b. Maybe the most important thing this book does for me is give me something to suggest back when some imagination-lacking person suggests Ender's Game as an intro to reading science fiction. Somewhat ironically, I feel like OSC himself might benefit from reading Some Desperate Glory, because, you know, learning how to escape a high-control apocalypse-focused group is an important life skill and some of us need to practice it more than others. I don't know if he still reads other people's books, though.