I like this idea, and would love to see it in LB. Unfortunately, search is quite a resource-intensive functionality and so we’d need to work out how to set up a system which has fast search for all users over all of the listens that we have in LB.
Out of interest, are you specifically interested in search, or do you think that an alternative navigation system might also work? e.g. if you saw a list of all artists that you listened to in the last 1 month (or other time period), and then you could click through to an artist and see all of their recordings that you’ve listened to, do you think that this might work? From a technical perspective, this is much easier to implement than search, and my intuition is that it should give you most of what you need.