I tried to enable the swap file on my HDD where the game is installed (not on system SSD, though) and it seems to fixed the crash problem. So, as a conclusion - either its real memory requirements are MUCH more than 16GB or there is too damn much memory leaks at its current state. My wife states that graphically the engine is virtually identical to Original Sin 2 (haven't tried the latter myself, so won't argue here), so the latter version seems true to me. Thanks all for a help and solution found!