1. In media res - character is falling
2. back in time a day or two - long chapter in which the character is doing his job and meets the baddy.
3 etc. moving on from there.
So I think I could add in a 2a - character and friends having lots of action and fun doing the magically real thing that the book is about before it gets into the drama
Have you read Save the Cat Writes a Novel?
If not, I would read that (as well as widely in your genre.. YA definitely has 'trends' and while you shouldn't rewrite the entire book to fit a trend, you should also check you're not trying to sell a variant of what was trending last year and is 'old news' this year).
From what I see right now things are moving away from fantasy set in the real world and into completely made up worlds (but check your specific branch of YA). Again, it's probably not practical to rewrite but if you see the trend has shifted and if (for example) the story moves to a fictional world in this book, you might want to make that clearer by introducing that possibility right at the inciting incident, (or if it's a series, and it should be, look for ways to move the book 2 into a fictional world).
For novels aimed at Young Adult or Middle Grade readers, we want a strong voice, excellent characters and a plot that keeps you turning the pages late into the night.
This, to me, is just a fancy way of saying pulp fiction... which in 2021 (imo) means fast paced 1st person 'easy' writing, cliffhangers at the end of as many chapters as possible, and a tight plot packed with tropes.
Does your book tick all three of those boxes? Pull up the MS, write a list of chapters, and tick each one that has a cliffhanger at the end. If it doesn't, sometimes it can be easily fixed by deleting the last 400 or so words. Then make a list of the tropes you have and highlight the ones with fresher takes. (Ideally you want a balance of giving readers what they want and surprising them with things they didn't know they wanted).
The summary (especially with adding in another chapter) seems quite slow paced to me. Going by Save the Cat the inciting incident (Catalyst) should happen at roughly 10% (so 6k words in a standard YA) but it's worth taking account the changing genre fiction market.
Half your readers will be young adults used to TikTok and serialised Wattpad fiction, the other half adults increasingly 'conditioned to seek instant gratification'.
So while I learned the Save the Cat rules, I've found much more success throwing that rule away and focusing on character depth + interesting situation intros to quickly ground the reader, then straight into the inciting incident before the end of chapter 1.
Long chapter 2, how long is long? In the YA / NA books I've done, the goal was 1500 / chapter and anything over 2k had to be reaaaaally justified.