Problem with indexes

Hello. I had the following problem:
PostgreSql version is 12. There is a table and it has any indexes. And the partitioning by date is used in the table. When I make a request to a view for this table with a filter, everything is fine, i.e. looking by index. And when I do sorting through ORDER BY it does not scan by index and my query works for a very long time. I know that a materialized view can be made, but I do not need it. Because the data must be fresh and there are a lot of rows. What can I do to scan an index with ORDER BY in a request for a non-materialized view?

show us table definition and execution plans. and switch to german if possible.

Andreas

Thanks you! Solved a problem. The problem was that in the view there is a call to own volatile function, it replaced with stable.