I’d pretty much rank your priority survival needs in this order-
You just need one. They are hard to make out of nothing and if you have one you can perhaps (not as easy as it looks on TV) improvise everything else.
Are you stupid? You’re going to drink Raw Water?! You selfish prick, I won’t even be able to eat your parasite infested and disease riddled body!
You need the Fire to process the Water (boil it for a while so it doesn’t kill you) and a container to hold it, but improv because the next thing you instantly need is…
Water!
You need to drink at least a Half Gallon a Day. You can only live 3 Days without it and dehydration is not pleasant at all. It’s about the most critical thing next to Oxygen. You can live without Food for a Month.
The previous two priorities are steps in getting Water, though they have other utility, and you can bypass them if you carry Purification Tablets or a Trail Filter both of which are very light.
I have other Bushcrafty thoughts but those are easily your top 3 needs.