It’s pretty early to drop to one nap. Could you not just cap the current two naps so that baby sleeps for 30 mins the first nap then 1.5 the second? You can play with the timings to see what works you may need a longer or shorter second nap to get the desired result. If it’s taking an hour to get to sleep baby isn’t tired at the time they’re going down x
We need a 4.5 hour wake window before bed, so if baby woke up at 3.30 bedtime would be 8pm. But I guess it's trial and error to see what wake window suits your baby! Ours was 4 hours then it went to 4.5!
Sometimes my nearly 10 month old only has 1 nap- we don’t have any routine- if she acts tired and falls asleep she sleeps- if she doesn’t want to sleep she just doesn’t 😅