Traceql query span with predict_linear function

how can I enable the predict_linear function on traceql query for span?
I am required to predict sales/inventory requirements using predict_linear.

By default, predicrt_linear does not work in tempo, but is there any other query that can achieve the desired results?

Also, I have explored metrics_generator, there are the following concerns using metrics generator.
its data duplication, sales data is already stored in tempo span which is being pushed to prometheus.
metrics pushed to prometeus creates duplicate data. e.g there is a single sell entry in span whereas in prometheus there is the same entry every 15 seconds for about 10-15minutes.