A really smart but depressed author (whose initials were DFW) once told me that endings are like non-parallel lines -- two lines eventually converge somewhere. If the ending is far away, then you can't quite tell where it is, or maybe it seems like the lines could go on for a very very long way (like train tracks). But as you get closer to the ending, the angle of the lines makes it clear where the lines are going to meet, even if you haven't written or read the ending yet. His policy was to never draw the point where the lines cross, because if you've written the point up that that well, the reader will be able to see where the ending will be. So it's boring and predictable to keep writing once it's clear to reader and writer both where it's going to end.
Not sure how that helps in this situation but it supports what proxybaba is saying. Leave it open. If the MC is fighting against incredible odds, then the non-parallel lines point towards defeat. You can hint or foreshadow that too, which makes the direction of the lines a little more clear. Or if the MC dies, then the open ending can be more about whether the MC makes it to the afterlife -- like maybe it's a scene of the already-falled friends waiting to see.