What is the difference between the Tor browser initiated by Firefox v68.9.0esr and Brave Version 1.10.97 Chromium: 83.0?

This question has already been answered but because you have a bounty, I can't mark it as such.

From Brave:

Brave includes best-effort defense against browser fingerprinting. Broadly speaking, browser fingerprinting is the detection of browser and operating system features that differ between users for the purpose of covertly identifying users and tracking them across the web. Although fingerprinting attacks will always be possible, it is worthwhile for us to make these attacks as slow / costly / difficult as possible.

Brave includes two types of fingerprinting protections, (i) blocking, removing or modifying APIs, to make Brave instances look as similar as possible, and (ii) randomizing values from APIs, to prevent cross session and site linking (e.g. making Brave instances look different to websites each time).

In cases where we block, remove or modify API behavior, we attempt to return empty, or non-identifying values, that have the "shape" of expected values, to minimize web compatibility issues.

In cases where we randomize API values, we attempt to make modifications that are imperceivable to humans, but distinguishing to computers / fingerprinters. These randomization values are derived from a seed that changes per session, and per eTLD+1. Third party frames and script share the seed value of the top level, eTLD+1 domain. This approach is especially useful in fingerprinters that hash together a large number of semi-identifiers into a single identifier, since randomizing just one value "poisons" the entire fingerprint.

Tor takes a different approach. It seeks to make everyone look exactly the same. If you modify the Tor Browser with addons, etc, you start to look different to a web server and therefore you are more easily picked out.

Tor Browser is dedicated to Anonymity. That is its single goal. Brave is a general purpose browser and is not dedicated to anonymity.