How to get entity from transliterated argument in URL?

Question

I have panel, where I have argument: taxonomy term name

term names are transliterated (like "My custom taxonomy title" into my-custom-taxonomy-title)

path is like this: my-custom-list-of-nodes/my-custom-taxonomy-title

How can I get in PHP code (in some hook) original taxonomy term name from argument "my-custom-taxonomy-title"?

Original string can have diacritics, uppercase, spaces. How can I detect Term ID from transliterated argument "my-custom-taxonomy-title" ?