The way Kodi on the RPi4 and v12 calculated the timestamp and the way Windows calculated it were different so it looked as though I have a LOT of files to copy.
Hi,
Files have some date-time properties, creation, last write, last access... probably that synchronization tool, in case of exfat partition doesn't use the proper timestamp pairs. I had some issue when I created a small program and needed to check the time when files where created. I used the last write time instead of creation time to avoid the issues.
I had too many issues with accessing ntfs partitions on linux, in my dual boot (W11 and Xubuntu) PC I'm using an exfat partition for "common files". If we talking about a media what need to be accessed with linux and windows too, the simplest solution is the exfat partition (it's not a common thing to use file synchronization tools with linux-windows devices). For "only linux", always the ext4 is recommended. And if really need, reading an ext4 partition on windows, isn't an impossible task too...