Yes, Free File Sync is excellent, and fast and more or less foolproof.
I use it to back up all my data locally, I have USB enclosures with M2 drives used in the traditional three generation rotation of backups. This uses mirror mode to the USB drive. You can choose an alternative synchronisation mode as necessary. It usually takes about a minute to do the backup unless you are reorganising the data..
I also backup my Thunderbird email folders (profile) locally, again in mirror mode. Due to the use of thousands of tiny files by Thunderbird, this takes 3 or 4 minutes for much less actual data.
Here is an example of a USB caddy. Of course you need three enclosures also three M2 drives, but it is not worth going beyond basic speed drives unless you expect to use them elsewhere. However, take note that both PCIe and SATA interfaces are available. I suggest you go for PCIe (drives and USBs).[edit – woops, item below is SATA]
If this is as clear as mud, feel free to ask for more information (but it is simple enough in the end).
https://www.scan.co.uk/products/akasa-ak-enu3m2-02-m2-sata-10gb-s-external-ssd-aluminium-enclosure-usb-31-gen-2-type-c