DD was born at 33 +2. She was only in NICU for ten days and was 4.4 lbs, also with no health issues apart from jaundice. She was too small/tired to attempt much breastfeeding when she was in NICU. After a few days I just pumped (like you I had no problem expressing plenty of milk) and agreed to give her just EBM so she could gain weight and get out of there ASAP.
She was also drinking a bottle every three hours and this schedule continued for weeks when we came home too.
I thought it would be impossible to establish full breastfeeding from this, but eventually managed it. I found it took a lot of time/ patience and that I had to continue pumping for weeks whilst we got it fully established.
Obviously all babies are different so the way I did it may not work for you, but we began by just doing little ‘practice’ feeds (whilst maintaining her 3 hourly feed schedule with bottles). I then slowly transitioned her, week by week, until she was fully breastfed.
After being home for a couple of weeks (once she was a little bit bigger and stronger) i replaced one bottle of EBM with one breastfeed every single day. After a week or so of that we tried doing two full breastfeeds instead of two bottles every day for a week or so. (And so on).
I didn’t rush it because I worried about her getting overtired (she was so little and sleepy at first), so decided to try and build up to exclusive breastfeeding over a month or two. We probably could have done it more quickly tbh, but ultimately it worked.
She’s now eight months and still breastfed. The only downside is that at around six months she decided she didn’t want to drink from the bottle at all, so expressing is no longer an option!
It would have been easier not to bother, but the bigger and stronger she got the easier it became.
Good luck with it!