Sleep training recovery with sibling?

Please tell me our sleep routine isn’t gone! Our daughter is 19 months old and we sleep trained her with Ferber then CIO, she used to take 5 minutes to fall asleep with our sleep routine. Wake 7:30-8:30, nap between 1-2pm, then bedtime at 8pm. Bedtime routine of dinner, bath, last wiggle stretch, read, and in crib sleepy but awake, she’d be asleep in 5-10 minutes no crying. We had minimal problems with this schedule before baby brother was born, sleep regression and teething. Teeth haven’t cut, sleep regression is guess is never ending as it started when brother was born and he’s not going anywhere. He’s 6 weeks old now.

Family coming to help has changed what nap time looked like for a period we were unable to get her to sleep except in the car this lasted a couple weeks. Then my husband was able to get her down for her nap by cosleeping. So now she cosleeps for naps and bedtime. She can be put down but the will wake up through the night and it takes 20-90 minutes to put her down. Her naps average what they used to before but again take 20-60 minutes to get her down and she wakes very grumpy.

For the past month we’ve been back to the old routine more or less but she’s been needing my husband to get back to sleep in the middle of the night. We don’t wanna do CIO as it seems like right now it would just make things worse with so much going on, and cosleeping isn’t sustainable with my husband’s work. We know this transition is so hard on her but is the old routine gone completely? Any advice or experience would be appreciated! I’m doing almost all newborn care alone and it sucks so bad cuz she really needs help too.