4 month sleep regression help

We are desperate for some advice regarding the 4 month sleep regression. Our 3.5 month old seems to be going through it at the moment with the maximum nap length of 45 mins and waking every 30 mins to 2 hours overnight.

Nothing we try currently lengthens the naps. Baby can self sooth and we put her down awake for bed and 90% of her naps (unless we are out and about in which she may fall asleep I pram/car etc).

We have a good bedtime and nap time routine that we’ve used for months to achieve the awake put downs.

However when baby is waking in the night they don’t seem to be able to self sooth anymore. They used to be able to. She just screams now. I don’t want to leave her to cry but I don’t want to create sleep associations.

How do you navigate this? I feel like we are creating sleep aids when we’ve worked so hard on getting her to go to sleep independently.

We would be very grateful for help - signed one very sleep deprived mum and dad!