Order get_terms by multiple meta_values

That is because get_terms() does not accept array type as a value for the ‘orderby’ parameter. The documentation says about this parameter:

‘orderby’

(string) Field(s) to order terms by. Accepts term fields
(‘name’, ‘slug’, ‘term_group’, ‘term_id’, ‘id’, ‘description’),
‘count’ for term taxonomy count, ‘include’ to match the ‘order’ of the
$include param, ‘meta_value’, ‘meta_value_num’, the value of
$meta_key, the array keys of $meta_query, or ‘none’ to omit the ORDER
BY clause. Defaults to ‘name’.

You can see here the original documentation page