I would go for nvme0n1p2 being Manjaro and nvme0n1p3 Swap:
nvme0n1 259:0 0 465,8G 0 disk
├─nvme0n1p1 259:1 0 300M 0 part
├─nvme0n1p2 259:2 0 456,7G 0 part
└─nvme0n1p3 259:3 0 8,8G 0 part
I would go for nvme0n1p2 being Manjaro and nvme0n1p3 Swap:
nvme0n1 259:0 0 465,8G 0 disk
├─nvme0n1p1 259:1 0 300M 0 part
├─nvme0n1p2 259:2 0 456,7G 0 part
└─nvme0n1p3 259:3 0 8,8G 0 part