I'm dealing with some similar problems, on a smaller scale. The first third of my novel is composed of short chapters that move the story along. All the emphasis is on getting to the main location. Then they're there.
Suddenly their days and nights become repetitive and wearying. This is part of the learning experience and something they need to go through. Obviously I don't want the reader to go through it in the same depth as the first part of the book (which spanned about a week).
In the last third (or more) of my book they're moving again and encountering new things, though there will be some repetition there too.
I'm dealing with it by shifting the time arc of the narrator.
Perhaps there's a name for this but that's how I think of it. My narrator is also 3rd person limited, with slight peeks into my MC's head (I have a couple chapters from other characters' points of view and get more into their heads).
Some of the narration happens in real time, more or less.
Not five feet away crouched the woman, pushing mud into the corners of
a form. She dipped her hand in water to smooth the top and finished
with a dusting of powder from the other hand, before moving on to the
next. Others, all grandparents—some so old they could barely balance
on their bent legs—did the same a few feet away. Children—all younger
than Simon—stood nearby, ready to pull up the forms and run them
elsewhere in the mist.
Sometimes the narrator uses details to compact a longer action, but one that is still within a fairly limited time period, in this case, no more than an hour.
Ruth tried everything. The fresh dates that reminded her of home,
soft chewy bread baked in rounds and spread with spiced lentil paste
and minced onion, squares of what looked like feta cheese soaked in
olive oil and herbs, and some fruits she didn’t recognize. Even the
water was delicious.
Time compression is going to happen more often than not, otherwise you'd never get anywhere. Real time storytelling usually happens with dialogue, but not always. Transitions often compress time and merge multiple actions into one.
When the sunlight was completely gone and the nearly half-full
crescent moon shone in the sky, more people began to filter into the
Sometimes the narrator needs to compress even more into a few lines. Here's where you can do things like describe a task in detail then add "as the days passed, he found was able to lift two boxes at a time, then three." Or show how his shoes are worn down and his shirt is tight around his biceps.
Or just straight up cram years into seconds.
After six long years, Sophie turned 15. She had one letter from her
parents, written a month after they left, and five postcards from
Gustav. The war was over. Renee’s parents moved to New York and she
left on the train to join them. Werner had to take a train and a boat
to meet his father in Australia. Eight children had the same news: No
one was sending for them.
In your story, bootcamp is going to end up being a disjointed memory for your character. Just like college or summer camp or 8th grade or any other long mostly-same experience is for someone. Days (weeks, months) run together. A few things will stand out, especially firsts. If your narrator uses past tense, there's no reason you can't describe much of the experience like an actual memory. Memories skip around. You might want to keep the chronological order of things but what's important will be brief details and the overall picture, not the mundanity of the in-between.