Wow, fixed. While writing the above it worked. I'm guessing it's just very slow. Could a programmer please speed up the program? I have a Ryzen 9 3900XT for goodness sake. Although I doubt Opera bothers using more than 1 core.
However I have noticed the speed dial now opens instantly, instead of excessive history slowing it down. Seems like one thing was tweaked which affected another.
Filed as bug BS-59611