I was about to recommend the Fatal Frame games if you’re looking for classic survival horror recommendations but on second thought they don’t really fit your parameters about descending into madness. They’re more about exploring haunted Japanese manors and villages with the protagonists themselves being mostly blank and static.

If you decide to check the series out, I would recommend you grab iso files of the first three PS2 games and play them on your nightly build of PCSX2. While 4 and 5 have been made available on all modern platforms, I don’t think either of them really showcases the series at its best. 5 is just a huge mess all around and while 4 is more in line with the PS2 trilogy, it’s still frustratingly railroady and trivially easy.