What filesystem to use for a 10 TB drive connected to router with DD-WRT and Mac?

I am going to connect a hard drive to my router and let the router share the drive through SMB. The purpose is to backup my computers using Time Machine. I realise that if I ever need to restore a large amount of data or have some issues with the drive, I might want to be able to connect it directly to one of my Macs. I am at loss about what filesystem I should use in such a situation. Fat32 - doesn't support volumes larger than 2 TB exFat - not (?) supported by DD-WRT (at least not out of the box) Ext4 - very weak support in macos NTFS - weak support in macos APFS/HFS+ - weak or no support in DD-WRT What are my options?