How can I figure if a query is CPU-bound or I/O-bound?

I have a query that runs regularly. It runs in under a second, but I consider it too slow and I would like to tune it. I can either monitor it as it runs live or copy the query text and run it myself. The query plan is a classic "[Wide, per-index updates](https://www.sql.kiwi/2013/01/optimizing-t-sql-queries-that-change-data/#1.-wide%2C-per-index-updates) " plan. It is almost identical to the below, with the only difference being that I have inserts rather than deletes. I am sure that my bottleneck is during the index-modifying steps. It is either due to CPU usage (the indexes are PAGE compressed) or the reads required to insert into the indexes (they are billions of rows). But I would like to know which it is! I can easily find the total time the query runs for as well as the time spent on CPU (sp_WhoIsActive and SET STATISTICS TIME ON both present this readily), but how can I specifically find the **time** spent on logical reads during this query? Ideally, I would specifically like to know the time spent on logical reads during the index modification steps. SQL Server 2022. Compatibility level 140.