Drop-down field values get changed by user

If you want to stick within Airtable’s native grid interface, there’s only one way of doing this that I can think of right now.

Create a linked record field, but in the linked table, change that linked table’s permissions so that the user cannot create new records.

There might be other ways of doing this that I’m not thinking of.

Interfaces and forms don’t allow new select options. Otherwise, within the “data view” of a base does not have granular enough permissions to allow someone to edit the values of a field, but prevent them from creating new select options.