I think I found the problem. I created a new profile, loaded up the extensions that I want, then imported a list of 1300+ HTML bookmarks, then did a new window, all is nice and fast. But if I go to the URL of my router in that new tab of the new window with no other tabs open, using this:
then open a new window, it takes 10 secs to display the image. The browser is hung while I’m waiting. If I close that window, then close Brave, then reopen Brave, then create a new window, it again takes 10 secs to display the image. Once its in that mode, there is nothing I can do except delete that profile, delete the User Data folder, copy a clean version of User Data to that location, then restart Brave. Then it will work as if it were a new installation, with new windows displaying the background image very fast. My router is an Asus RT-AC86U with Merlin 384.16 inside. I have no idea what that website is doing to Brave to make it misbehave. It does not appear to have that effect on Firefox or Chrome. Let me know if you need any further info.