I had to dig up the ancient Gaijin post on the system they used to specifically enhance visibility for Simulator mode (from back in 2015):
https://old-wiki.warthunder.com/Visibility_mechanics
In particular these paragraphs:
In our Simulator Battles, which are designed to reflect the battles of the Second World War with maximum authenticity, there are no markers. This is to avoid ruining the lifelike image with extraneous elements. Alongside this, vehicles are much harder to see than in real life – to be precise, it looks like if you were watching a real-life conflict through an action camera fixed to the pilot’s head. Though in fact it’s a little better thanks to a lot of work done on making the game more lifelike than a digital video camera. To be precise, “contacts” appear at distances where the aircraft is definitely no longer visible. But before this, there are moments when the plane is very hard to see – it’s just a few pixels, after all! – but is not yet covered by a “contact”/“fly”, because this covers up the orientation and manoeuvres of the aircraft. At these (“medium”) distances, aircraft were very easy to lose from view without markers.
In update 1.53, a special detalization level has been created for aircraft at medium distances. In practice, the game draws the plane at another viewing angle and with a higher resolution (super sampling anti-aliasing) so that it doesn’t disappear entirely from view. Accordingly, at medium distances a plane might seem small, but will remain noticeable enough now, and without losing its shape or outline. Along with the new rendering (link), which makes maps more realistic in terms of lighting and diffusion (and accordingly less contrasting at long distances), this significantly improves the ability to track and detect a target in an aerial battle, making battles more comfortable. We hope that fans of flying will appreciate this innovative concept.
At the same time, the image dynamic range was increased 8-16 times, and this means that if earlier at shorter ranges (up to a kilometre) a glimmer on a plane’s wing could practically “disappear” before by blending in with a neighboring non-glimmering surface, then now you can more precisely detect an enemy aircraft’s orientation and the manoeuvres they’re performing.
Based on he feedback above, it feels like the placment of “the dot” for extremely long range target has been put back, but the “special detalization level has been created for aircraft at medium distances” is still missing after the Leviathan launch.
I personally use a 4k monitor on max res, and cannot see any aircraft outside of about 2km, if the target is against the ground. Even against the sky it’s extremely difficult (major eyestrain). Basically it’s almost impossible to keep track of SA in any real way, if there are multiple targets in the area, compared to pre-leviathan, where I could easily keep general tabs of what was going on around me both in a dogfight, and including targets in the medium range zone.
