Vietnamese coffee maker is my solution
Bought it in Vietnam in 1997 - pretty confident it's aluminium.
Makes a nice little espresso shot. I make a perfect (for me) double espresso shot with 3 teaspoons of ground coffee (on our sunbeam bur grinder set to a fine 4 - there may be a more optimum grind but this is what I use and it works nicely) and 120ml of recently boiled water.
It just sits on top of my mug. weighs a meagre 21gm. 55mmx90mm with room to stuff your ground coffee in it for a few days hike.
Here's how to use it (umm but for me without the condensed milk) https://youtu.be/SijXazsElZQ
I enjoyed the music in that video.
It looks like a variation on the pour over coffee method. One thing I noticed is that you use twice the amount of water recommended in the video (120ml vs 60ml). This will of course have an effect on the coffee strength. Since you compare it to espresso or a "short strong shot of coffee" I was curious how strong it would actually be.
It's impossible to determine the strength precisely without measuring, but we can estimate a range. Three teaspoons can be anything from about 15ml (level) to 20ml (heaped). Similarly, the ground coffee bulk density can vary from around 0.3 to 0.5g/ml depending on the coffee type and level of roasting. Extraction is usually in the neighborhood of 20%.
Putting that all together and dissolving it in 60ml of water and you get a coffee strength of 1.5-3.3%.
If you use 120ml of water it would be 0.7-1.6%.
Typical pour over coffee is 1.2-1.8%. Espresso is in the range of 5-15%.
So I would guess your method produces something that's possibly normal coffee strength but then again could perhaps be on the weak side.
If it were me I'd go with 60ml of water and plenty of that sticky white sweet condensed milk.