GrapheneOS's hardened memory allocator is why Osmand crawls on your Pixel
GrapheneOS – When an app is slow
After a year on GrapheneOS, one app—Osmand—ran noticeably slower than on other Android devices. The culprit: the hardened memory allocator, which adds significant overhead for map scrolling. The fix is simple: long-press the app icon, open Info, go to Exploit protection, and disable only the hardened memory allocator for that app. Osmand speeds back up, with a small security trade-off the author accepts.
The reason behind it is the hardened memory allocator, which seems to create a significant overhead for Osmand. That might be because scrolling a map requires constant loading and discarding of data.