Migrating content with referenced taxonomy field is to be migrated by term name Is it possible to migrate content with term reference fields, but instead of referencing terms by their tid they are referenced by their term name?

instead of this:  

field_tags:
  plugin: sub_process
  source: field_tags
  process:
    target_id: tid


Do something like this:

field_tags:
  plugin: sub_process
  source: field_tags
  process:
    target_id: [term name]
i guess entity_lookup what you looking for:
here is an example from migrate_plus/src/Plugin/migrate/process/EntityLookup.php

field_tags:
       plugin: entity_lookup
       source: tags
       value_key: name
       bundle_key: vid
       bundle: tags
       entity_type: taxonomy_term
       ignore_case: true