In all likelihood the foveated rendering is only being applied on a late-stage rendering pass (eg: post-processing), which will effectively make everything low-res as you expect. However the earlier rendering passes, where the actual heavy part of the rendering is happening, are not being properly picked up. Hence no good gain in performance. This is what was happening after SU10 in MSFS2020 until the heuristic was “re-tuned” to property pick up the necessary rendering passes. A tool such as PIX would help validate that this is indeed the issue.