Whereas \w+,\s(\w+) is processed without problem, the "complex" \w+,\s(\w+\s\d{1,2}) could not processed within an acceptable time.
Display Filter had no problem with the "complex regex", but cannot be used in my case because I need to make a replacement.
The "solution" was to replace \w with [a-z] (case-insensitive). Even [a-z0-9]+,\s([a-z0-9]+\s\d{1,2}) brought Find to its "knees".
This behaviour concerns Studio 2019.