EmEditor Professional 7.00 beta 26 makes some progress in speed.
But Regex replace for big file is still slow.
Comparing with UltraEdit,you will find making same Regex replace UltraEdit is very rapid.
It takes EmEditor several minutes.
It takes UltraEdit less than one second,almost instantaneously.
I couldn’t find your sample file. The URL is an HTML file but it doesn’t contain tag. Also, what do you want to replace that text with? You may send me a sample file to firstname.lastname@example.org.