I'd get some Swaddles- either old fashioned kind or modern zip/velcro etc ones. Also-

Nappies - disposable or modern cloth nappies.

Wipes. I use cloth wipes. Either just with water or coconut oil.

Old fashioned cloth nappies. Like the little white towels. They are excellent all-rounders. I keep some beside my bed, in car, in pram, in nappy bag. Good to clean up vomit, exploda-poos, spilt anything, place over change tables in public toilets, use as a bib, etc.

Wouldn't bother with formula or bottles if you are serious about giving BF a go.