Grant Fritchey gives us another option for determining whether an index is in use:
One of the most frequent questions you’ll hear online is how to determine if a particular index is in use. There is no perfect answer to this question. You can look at the sys.dm_db_index_usage_stats to get a pretty good picture of whether or not an index is in use. However, this DMV has a few holes through which you could be mislead.
I thought of another way to get an idea of how and where an index is being used. This is also a flawed solution, but, still, an interesting one.
What if we queried the information in Query Store?
Be sure to read Grant’s warning before jumping into this, but at least it gives us another option, as well as a better understanding of which queries are using particular indexes.