So I had sudden issues with brave being unresponsive and slow to do absolutely anything.
Other browsers did not have this issue, I read through this thread > brave-is-very-slow and found many people to be having the same issue.
There was no solution found that worked for me so I decided to figure it out myself and found that what helped instantly was changing the setting Get Started > On start-up > Continue where you left off to Get Started > On start-up > Open the New Tab page.
There are no steps to reproduce some people had the issue continually while others did not.
Im using Ubuntu 20 but the issue is persistent across platforms
Maybe this helps solve the issue for others, it isn’t really a thorough solution it’s more of a workaround since the feature should work, let me know what happens.