Hi wunderlustig
If I were in your situation, I would try to follow cues to get a new routine going. If you lo is 10 months old, I am guessing that 2 hrs A time is not long enough for her to require a nap any longer than 40 minutes. then keeping her up til the next nap time may be too long, resulting in overtiredness.
Do you know the tired signs your lo shows. Are you able to do the wind down when she shows these signs? Like yawning, ear pulling, eye rubbing, red eyes/eyebrows, getting hyper/getting slow or uncoordinated. Or getting whiney.
If these tired signs happen at 2 hrs, then try extending by a little bit each day. If they are longer, see how it goes. My lo is only 7.5 months and already has 3 hr awake times, and this is not uncommon for her age according to the birth club thread.
Also, while your lo is short napping, you may need to offer more than one nap in order to prevent overtiredness - this may help your early wakeups.
There is also a support thread for short nappers in the napping area, feel free to check that out for more ideas, but I think your short naps and early wakeups are routine related and if we can tweak that, things should improve. You are already doing well on the night sleep improvement, so lets see if we can fix the day sleep too.
Rina