to be perfectly blunt, I think that apart from sakura, lsm was a super last minute group
mhj indicated that she was hired for a new girl group under source/hybe in 2019, and that their debut song was decided 2 years ago before she had "creative differences" and was allowed to continue her own vision in ador
kazuha literally started training 4 months ago, chaewon and yunjin joined hybe 8 months ago, eunchae's trainee period was 1 year; all a really short time period to settle in everything compared to mhj who makes a big deal about handpicking all her trainees and spending all that time going through mock high school experience in korean and english etc
so my guess is that sometime before august 2021, there was some sort of faction infighting in hybe that led to mhj to do her own thing, taking the trainees she chose and trusted staff along with the plans she made beforehand to ador, letting the other faction(s) in source to lead their own group
and since they were expected to debut a gg around lsm's debut, they kind of rushed things to accommodate for the fact that they had to essentially start a group over from scratch so they didn't have the time to do so