How can I get my baby to self soothe

First of all, I know this is my fault for not letting him self soothe as a newborn and always rushing to him at every sound.

Our baby is 25 weeks and he is strictly breastfed. We have tried him on bottles and are hoping to accomplish combi feeding, but at the moment we have no luck.

Our baby does not have dummies/pacifiers. During the day he can fall to sleep by himself, but at night he constantly wakes and doesn’t fall back to sleep unless I breastfeed him... I know it’s for comfort and he’s not hungry because he has multiple feeds before bedtime. He falls to sleep between 8-9pm and then wakes up around 2 hours later, we have tried letting him cry it out but after 5 minutes we have to give in as he has woken himself up properly from crying, so I’ll feed him. He will then wake up multiple times during the night and will want to be breastfed to settle until he wakes up between 6-8am ready for the day.

We really need any help we can get. I am honestly so shattered having to sit and breastfeed him all night. How can we get him to self soothe?

Thank you