How to fix a toddler’s sleep schedule

Hi!

if possible someone could help me out!

I have an almost 3 years old girl 👧🏻 she wakes up at 8:00 am (when i wake up) and has a nap at 12:00 pm, and falls asleep at 8:00 pm.

This was her routine, now it takes me more than an hour to put her to sleep, i have to lay next to her for an hour or more.

Her routine has gotten worse, she wakes up at 9:00 am, refuses to take a nap, so it’s like 2 hours preparing for the nap, therefore naps at 2:00 pm, which makes her stay awake until 9-10 pm.

If she doesn’t take a nap she’s overtired and doesn’t sleep well at night, cries or has nightmares but sleeps at 7:30 pm.

I know i might have wrote a long story 😅 but i have a new baby now, and it’s almost impossible to leave him for more than an hour, and sometimes he’s awake so it’s really hard.

Btw this started before having the baby.

I appreciate all your suggestions!

Thank you!