The reason for boiling water when mixing it with the formula is because the formula itself is not sterile. therefore, mixing boiling water with it would kill any potential bacteria. Many people don't follow this because they don't know or just because whatever personal convenience work for them. In the end, I would say it is not about what everyone else is doing but really what you feel is better and about the risks you would like to take or not.
We did water from a Brita pitcher fwiw
is your tap water not safe to drink? seems like it could be more cost effective to invest in a water filter, even just a countertop pitcher style, if your tap water is safe. you’d avoid the PFAS and microplastics from bottled water too. what water do you drink?