Noroi - The Curse (2005, Japan) Supernatural first-person video documentary style POV, but with higher image quality than Blair Witch Project for example. No jump scares, just very creepy and unsettling. Slow burn, but good pacing IMHO. No weaknesses IMHO, hence on top of my list. Just a very unsettling and disturbing, almost real-feeling, horror movie.

Also good:

• A Tale of Two Sisters (2003, South Korea): less horror, more artistic, intelligent and original. Great story
• Shutter (2004, Thailand): my favorite jump-scare horror with cool effects
• Incantation (2022, Taiwan): great supernatural slow-burn horror with a cool twist
• Hereditary (2018, USA): great supernatural slow-burn horror, original as well
• Sinister (2012, USA/UK/CAN): great supernatural horror
• Event Horizon (1997, USA/UK/CAN): great sci-fi horror, very unsettling
• REC (2007, Spain): one of the best zombie style movies and also one of the most horror-like ones
• It Follows (2014, USA): kind of a stupid plot but it works. It's original, well executed and unsettling (supernatural)
• Smile (2022, USA): an even more stupid plot, but also well executed. The ending is bad. But it still terrified me so it works at its core, and that's all that horror films need to do (supernatural)
• As Above, So Below (2014, USA/France): the weakest one on this list but it's very original as well, I like it because of that