Personally, I don't think bottle-feeding has to interfere with breastfeeding. I think the feeding technique and the bottle nipple flow rate make an enormous difference. Research indicates babies suck the same on bottle nipples IF the flow rate does not overwhelm their oral space/airway. Another LC colleague and I tested a bunch of nipples for flow rate; found all disposable hospital types to be too fast, although one seemed better/a bit slower than some others. A few commercial brands appeared to be OK (and parent feedback concurs) but NICUs are likely to be hesitant about bottles/nipples being brought into the hospital. In spite of mother, LC or other health professional opinion/bias, there is NO "perfect" supplementary feeding device...
For example, there's no evidence that finger-feeding results in better (or worse) long-term BF outcomes -- transition to BF, BF duration, etc. than any other supplementary device. The tissue on the finger is not the same as the tissue of the breast. It can help the feeder notice changes in an infant's ability to "organize" re: sucking, but it can also result in oral "pursing."
The SNS or Lact-Aid nursing supplementer is not designed to help an infant "learn" to BF; an infant needs to be able to BF fairly effectively already to use it. However, it can be a great way to offer extra nutrition and increase production when an infant is BF fairly well. Negatives reported with this type of device -- can be messy or a pain to use, clean, etc. and some babies get "hooked" on the tube.
Re: NICU nurse and protocol about teaching 2 different methods of feeding -- request a copy of that protocol and read it closely. Ask for the research report evidence upon which it should be based. If the protocol is as described, it makes NO sense! Penga's learning (or trying) to coordinate breathing with sucking and then swallowing. BF is the biological norm and associated with infant body systems' stability, so should be 1st on any list; bottle-feeding (including flow rate) should simulate BF.
It would be extremely helpful for the OT's education to have her observe BF. However, it may help to BF before bottle-feeding (or finger-feeding, etc). Or, if Penga's really hungry, give her a little by bottle to decrease hunger, then BF, then can finish by bottle. Lots of moms find the best routine is to be available before a feeding, pump (so let-down isn't too strong), kangaroo, let kangarooing "lead" to BF (with or without a nipple shield based on baby's ability/energy/etc.) for 5-15 minutes, and finish with EBM (fortified or not) via a supplementary method. (Because preterm babies have less mature oral structures and lower endurance, they can't keep up with "organized" suckling as long as term infants, so limiting BF activity to avoid "disorganized" feeding behavior with the supplement is pretty typical in NICUs -- and generally makes sense.)
Personally, I wouldn't be concerned at this point re: Penga associating you with other kinds of feeding if it means she's in your loving arms instead of a staff person's for feedings.
Poor Penga with the desats... How scary that must feel for her. Question -- was the number different or her response to desat different with BF vs. the bottle-feed? I'm surprised the kangarooing didn't help her stabilize more quickly.