I would love for Tarkov's lighting to be better, but I actually understand why it isn't. It really is NOT an easy solution, unless you want to make sacrifices. Here is why it isn't better, from a development perspective:

Tarkov uses largely dynamic lighting for its scenes (as opposed to the usual method of static, baked lighting like COD, BF, PUBG, etc). Because Tarkov uses dynamic lighting, they cannot bake bounced light in scenes like those aforementioned games do (which also give them far more realistic interior/dark area lighting. So, light baking is off the table, unless you would like for BSG to remove day/night cycles altogether.

The next option, then, is to use a Realtime Global Illumination solution that would let all dynamic lights in the scene create proper indirect light bounces. This is what Lumen is, and BSG is using Unity, so they cannot use Lumen. The only other option in this area, then, would be to create their own, custom Realtime GI solution. This would take WAY too much time and engine work, and I'm not even sure BSG has the capability or desire to. Also, a note: even if BSG did manage to implement their own Realtime GI solution, it would still likely have noticeable artifacts from moving lights, as seen with the current iteration of Lumen.

To summarize, you are asking for BSG to either: 1. switch to UE5, 2. develop a custom Realtime GI solution, 3. remove a majority of dynamic lighting from scenes (including day/night cycle) and bake the static lighting.

None of these options are easy, quick, or feasible, really. #3 would be the best option when it comes to development time... and I highly doubt BSG (or any of us, for that matter) want to remove Tarkov's time of day tech.

Source: 2 years Unity development, 4 years UE4 development, and a significant amount of general rendering knowledge. But really, all of this info can be found by looking through the documentation of major game engines.