Do I Need exiftool?
Only if you want the command line. It is excellent and free, and it is not the only way.
exiftool is the reference tool for photo metadata. If you already use a terminal it is probably the best thing you can learn for this, and it costs nothing.
It does expect you to know what you want. For a Takeout export that means understanding the sidecar naming, which dates to prefer, and how to handle the truncated filenames, before you write a command that touches ten thousand files.
Takeout JSON Metadata Fixer encodes those decisions so you do not have to make them. It runs on your own computer and is free for your first 500 photos.