What key should I choose for the client database?

Question

Database design

We plan to create a single customer base. Now we are collecting client data in 3 software 1C, ERP, CRM (all 3 are not interconnected). We want to make Surname + First Name + Mobile Phone a unique key. Managers record all other data not always and not always correctly.
1. Is this key correct or are there pitfalls?
2. What to do if the client was recorded in transliteration (is there a standard transliteration library?)

Destination B2C tourism

Answer 1

Choose a surrogate key.

Answer 2

Last name and first name can be changed. Cell number too.
Unique, in theory, should be SNILS.