Quite difficult to debug as system is unresponsive when it happens, so would have to delve into logs. Maybe a Chrome memory management or graphics acceleration issue, I don't use many extensions but it's possible I guess. 12GB of RAM, but that can get eaten up by Chrome pretty easily.
I use ungoogled chromium, try the flatpak, new binary doesn’t work in Ubuntu, works great for me. Try with them all off and turn them on one by one.