"Dishonored 2" has switched Unreal Engine 3 through the Void Engine. This latest Arkane Studios game, is traded Unreal Engine 3 for the Void Engine, and that may not have been the most sensible decision, as there have been a number of reports of performance issues with the game.
There have been some updates available to resolve the issue, but the truth is that the second iteration of Dishonored is still far from perfect, especially on the PC. Even on consoles, despite running at 30 frames per second, "Dishonored 2" can attest to some sharp drops of fps, which makes even users of a PlayStation 4 Pro and a 4K television do not benefit from great performance improvements.
To benefit from the supersampling, it is necessary to manually download the 4K TV resolution to 1080p. However, this does not raise the frame count and obviously does not translate into greater visual fidelity, as proven by Digital Foundry tests of "Dishonored 2."
For the moment, the Arkane Studios have no intention of launching "Dishonored 2" patches that can facilitate gameplay at higher resolutions without compromising performance, but the situation may change in the future. What is certain is that the studio has other issues to solve, perhaps more pressing, which makes support for PS4 Pro not a priority.
As a conclusion, the players are still waiting for the improvement of this issue. If it has fixed, the stunning graphics of "Dishonored 2" will have no fps issue and enjoyable to play. Hopefully, the studios does not sacrifice a long time to fix.