Welcome to the community. This is an issue that seems to have popped up recently. An installed extension was causing the issue in many cases, but since you’ve already tried disabling all extensions, your issue must be something else.
This topic, Unable to sign in to google accounts (clear cookie error), is very similar to yours. There are troubleshooting steps suggested by support that you may want to perform to see if it changes any behavior. Please post update with results if you do.
Brave support is still investigating the issue. Their last post was 5 days ago. You may want to track that topic as any updates will probably be posted there.
Take care. 