Please note, I’m not speaking about the Extension itself, but the app version of Google Keep instead. While it is possible to add it to Brave, you cannot sign into it, the error it gives is:
This site can’t be reached no-thanks.invalid’s DNS address could not be found. Diagnosing the problem.
DNS_PROBE_POSSIBLE (DNS is definitely not an issue on the machine in question)
I’m guessing this may be a limitation due to being built upon Chromium rather than official Chrome, but I was just wondering in case it could be made compatible.