The page appears to be broken in the Brave browser. I uploaded a copy of the console to pastebin: https://pastebin.com/gsphX9z4
It's an issue of Brave blocking webgl content (iirc). It's too much hassle for me to install another browser to try fixing it, sorry.
Thanks for the info. It gave me some additional ideas. I found I can get the site to work if I allow fingerprinting.