My vendor was fully found by the website. I think, it is a good idea to make it private because none of other browsers revealed this data.
“none of other browsers revealed this data” sounds incorrect. I visited coveryourtracks.eff.org on Safari, Chrome, Firefox and Brave. Only Brave got “strong protection against Web tracking” AND “your browser has a randomized fingerprint” with default settings.
About WebGL vendor and renderer debug strings specifically: we’ve experimented with farbling them by default, but this deviation from what every other browser is doing causes too much website breakage for not much privacy advantage. Fingerprinting protection is always a balance between website breakage (or webcompat) and privacy protection. Brave’s fingeprinting protections are already best-in-class.