No judgement here at all. From reading the guidance, If you're adding formula to your nuby you should wash and sterilise after every use.
An alternative to this (if you haven't tried it already) is the hot shot method. Hot shot method includes adding 1 - 2 oz boiling water to the bottle along with your formula and then adding the remaining boiling water to your nuby to cool. You can then add the cooled water to the bottle and it should be ready for baby to feed (obviously test the milk to make sure).
By adding only boiling water to the nuby you don't have to sterilise each time. I don't believe the NHS support this method but they don't condemn it either, and Aptamil share it frequently via social media. There are also lots of parents (from what I've seen) using this method, myself included (previously). Obviously you should do what you think is right, whether that's following the NHS guidance or choosing your own path.
I have a reflux baby (now 4 months) and put him onto anti reflux formula (at 2.5 months) and he's SO much better now. He still has bad days where he brings some milk up after feeds but it's a huge improvement from normal milk, where he was being sick after almost every feed (started at around 1.5 - 2 months)
If you're worried speak to your HV about potentially moving onto anti reflux. You can find all of the symptoms via the NHS if you think it's more than just normal spit up.
Don'f feel bad, your bubba is more resilient than you think. You're clearly a great parent because you're expressing that you're worried about her. You're doing a fantastic job, it's not easy looking after a baby xx