I'm also having this issue with my Dell Inspiron 15 7000 2 in 1 laptop... I initiated the 24H2 update yesterday morning around 9am and I left my laptop on overnight to finish the installation since it didn't finish at all that same day - not even the download stage was finished before I went to bed at 1am this morning - when I woke up this morning at 8am, the download stage was done and the install stage was at 39%..... it's been almost 2 full hours since I woke up and it only progressed by a single percentage making it 40%... this is a prime example of why massive software companies MUST double and possibly even triple check their software releases before they move it from Beta to Stable... the average computer owner doesn't usually have the money to simply replace or repair a PC that's been nearly bricked by a faulty operating system update....
Also....
Holy freaking hell peoples... please have at least some pride in your public image... most of these replies are so infested with crazy spelling issues and insane grammar issues that they took me several read through attempts to figure out what you were trying to say.... many of them sounded like the writers were trying to use some weird false L33T Sp3ak... using L33T Sp3ak was considered "cool" back in the 1990's but it just makes you look dumb in the 2020's....