Where is the best place to make a request in vue.js on the front or back?

Question

Express.js

Tell me pliz how to do it better and it will be more correct?
There is a kind of CPM where the front is on VUE and the back is on express.js and mongoDB. It is
necessary to implement sending notifications to all clients (there may be several K per user). So, it’s better to get the customer base at the front through the store and transfer the axios to the back (the functionality is already implemented there) or simply transfer the user’s id to the back, get a list of all his clients in the same place and make a newsletter.
The question arises that if you get the entire database on the front, then this will probably affect performance if the data array is large (although if the user went to the section with clients before, they can already be stored in the store anyway). How would it be more correct?