It is a bit tricky, but YES, I do think cutting back the nap length will help in the short term. Usually, earlier mornings at this age indicates too much day sleep. For starters, you can make nap 1:30-2:30, if you prefer the 8:30 BT. If you want an earlier BT, shave the nap and make it 1:15-2:15, BT 8:15.
Am I correct to say that she was sleeping about 11 hrs a night, with 1.15 nap? so about 12.15-12.45 total sleep?
It's common for toddlers to drop sleep need as they get older, and then to either level out or lengthen again later around Kindergarten time. She may be going down to 11-12 hrs max for her sleep needs... as she is now sleeping 10 hrs a night with 1.15 nap.
It'll be quite a balancing act between school schedule, being stimulated and tired for nap bc of school, proper and age-appropriate awake times, NT, and BT and night sleep.
8-7 was my ideal sleep schedule, too! but I could ONLY get it if DS didn't nap. But it meant he was super tired after dinner and would fall asleep at 7, which meant a 6 or earlier wake up. If he napped for any length, his nights would be 10 hrs and less sometimes. At that age, he still needed his naps but could handle a day here and there without it. It is another one of those messy transition phases.
Here's an article about the 1-0 if you haven't read it already.
https://babywhispererforums.com/index.php?topic=244514.0