My lg is only just getting better. She had a tongue tie division about 5 weeks old and has been on 2 sachets of gaviscon since 4 months which did helped a little. We stopped using the prep machine about month ago and it’s reduced the sick quite drastically. We’re on one sachet now and she’ll only have a tiny bit of sick every and then. Now we keep a flask of hot water on the side and use a hot shot to make the milk. We use an extra empty bottle to measure the cold water and just use tap water to top it up. It’s actually quicker and easier than the prep machine and wish I’d done it sooner!
Definitely worth not trying not using the prep machine, we found this seemed to help baby settle a bit more, this was months ago though. I personally wouldn’t bother swapping at this late stage as it could end up causing more issues and stress especially when you might be looking to reduce/stop using formula in the next wee while. My friend baby is still quite sicky and she says ‘its not a medical problem just a washing problem’ so she is just riding it out. Im sure its been tough though!