What filesystem is currently best for a single nvme drive with regard to performance read/write as well as stability/no file loss? ext4 seems very old, btrfs is used by RHEL, ZFS seems to be quite good… what do people tend to use nowadays? What is an arch users go-to filesystem?
Ext4 being “old” shouldn’t put you off. It is demonstratively robust with a clear history of structure integrity. It has immense popularity and a good set of recovery tools and documentation. These are exactly what you are looking for in a filesystem.
I’m not saying EXT4 is the best for your requirements, just that age of a file system is like fine wine.
Calling Ext4 “old” is like saying that MySQL isn’t webscale