EXT4 is your all-rounder. Unix feature complete and reliable. No actually big downsides that would mske it insufficient for, well, anything.

BTRFS is your complex and feature rich option. All the modern file system features like copy-on-write, snapshots, subvolumes, deduplication. Good for putting an operating system or user files on. Stuff you might want to snapshot or sort into subvolumes, etc.

XFS has some neat features too, but it has one main focus, performance. The difference isn’t massive since it’s just a file system, but for the fastest transfers speeds, with the smalles CPU impact, nothing beats XFS afaik. It’s also fully unix feature complete, so it has no trouble with symlinks, hardlinks, permissions, etc.