For emergency use, Iād go with something simple and reliable like a Sawyer Mini or LifeStraw ā both are lightweight and easy to use without much setup. Boiling is still the safest backup if you can manage it, especially for questionable sources.
It also helps to carry purification tablets as a backup in case your filter fails. I was looking into different options recently and found a useful breakdown on [url]Outdoor Searcher that compares filters vs tablets for emergencies ā definitely worth having both methods covered.
https://outdoorsearcher.com/