I have 3 girls and bath and bed time are an issue here as well. There is a bunch of mumbo jumbo about kids clocks and Rythm being different that you can read but I can tell you what works for me.

We have an established bed time and a schedule they keep or suffer the grounding that ensues. Bed time is 9pm for mine period no exceptions. Quite/wind down time i.e. no more TV, phone, etc. is one hour before bed time. They can spend 45 mins of this time reading or playing a game what ever. Cloths for the next day are to be laid out, baths had, prior to 8pm period no exceptions. Getting baths earlier seems to help and avoid the last minute rush that the fights often ensue from. We do homework starting at 4 start dinner at about 6-6:30 and baths are done while we cook, hair dried etc. I flip a coin for who goes first as my two oldest always want to drag around. 8:45 is teeth brushed and in bed, tuck in and lights out at 9 sharp.

We had to be firm but having a set schedule clearly conveying expectations and standing by them with consistent consequences really helps. That and starting early to avoid getting behind the curve and the last minute rush. It takes time and energy but after a couple of weeks it becomes routine and helps.

This along with posting grades on the refrigerator every Thursday is two of the best things we have done for keeping things working for us. We have an 85 and higher grade limit. If you are below the cut off you are grounded, no phone, no friends over, no grandparent spend the nights until your average in every class is above 85. Most schools do power school so you can pull grades any time posting on
The fridge makes it clear to everyone where they stand.

I am sure some will think this is harsh but so be it the world is cruel and harsh and despite all the snow flake bull shucks we have to teach them to be responsible for themselves and their own actions. Granted all this takes time and our girls know they can get all the homework and study help they need by asking so it takes effort on our part as well. My oldest was struggling last semester due to missing a bunch of class for sickness and theatre so the last two weeks of the semester We literally checked every math and English problem on homework and take home test and made her work and rework them. She ended up with 3 89’s but missed 25 classes( 7 periods per day so about 4 days total) so it worked but it was work for both her and us.