This thing is actually working, BUT every single game it crashes with a Fatal Error.
So, when using the Vulkan renderer, War Thunder fails to render a lot of stuff such as trees/bushes, fences, objects and even small houses.
The reason I say sort of is because, and this is gonna sound really dumb but bear with me here, it depends on your tanks position. So on some maps, it'll only render trees that are to the north of your tank; if you've got a northern spawn, there'll be basically no trees anywhere but behind you, whereas if you spawned on the south, tough luck, it's basically unchanged. Still, it could be a nice advantage from time to time.
So here's how you actually do it:
1) Go to your War Thunder folder, open the "content" folder in that, and create a file named "pkg_vulkan.rq2". Run the launcher, it should download a few files. Also, while you're here, it might help to lower some settings, as vulkan will drop your FPS a little bit, but it shouldn't be too much of an issue unless you're playing on a literal potato. And select windowed mode, this'll let you know if you've done it correctly.
2) Close the launcher, and open your War Thunder folder, in it open the win64 folder. Create a shortcut of "aces.exe", right click it, open it's properties, and add -forcestart -driver:vulkan at the end of the "target" field, AFTER the quotation mark after aces.exe.
3) Run the shortcut you just created. If you've done everything right and put it into windowed mode, the window should be named "War Thunder (Vulkan, 64 bit)". Voila! Enjoy the clutter-free view of all of your opponents.
===Not working?===
Edit file config.blk with any proffered text editor. Find keys renderer3:t="auto" and driver:t="auto" and change "auto" to "vulkan". Save config. Either don't run the launcher after this, or set config.blk to read only. This will force WT to use Vulkan, if it doesn't for some reason.
This thing is actually working, BUT every single game it crashes with a Fatal Error.
This doesn't seem to work anymore, always have foliage and everything render regardless of having followed your instructions.
Did you run it in windowed mode to make sure you've got vulkan enabled? The window name should be something like "War Thunder (Vulkan, 64bit)". It still works for me, have you tried the config.blk method? Have you set it to read-only?
Also, keep in mind, it works based on the location of your tank. E.g on some maps, it'll only render trees that are to your north; if you got north spawn, you'll have clear view of the entire map, and if you spawned in the south, well, it'll be like nothing changed. (It can be anything, not necessarily north-south; on Kursk I know it runs from west to east, so you have to flank by the C point to use it to your advantage).
Welp, with 1.85 it's officially fixed. :\