ucharclasses package is very helpful for automatic font switching based on Unicode blocks. However, it is very, very slow.
One way to speed it up is to restrict its scope on certain Unicode blocks/scripts by giving the blocks or block ranges as an option. Unfortunately, this can have negative side effects when blocks are encountered, that are not selected at package load time. (see also the discussion around my previous question here: How can I use ucharclasses to change the font for a special script and then restore to what it was before?)
Ideally, I'd like to avoid restricting
ucharclasses to certain Unicode blocks and load the package without any options. Is there any way conveivable to speed up the usage of the package? Potentially by rewriting parts of the package?