That NewCacheStore() call has prefill==true which iterates all the services in the database, and for each service iterates every operation for that service (happening here). Iterating the entire database in several serial iterations is what is taking the time there, not starting badger, which happens in 411ms in the logs from your original post. There are certainly more efficient ways to query badger than the ways done in that cache prefill logic.
Also note in the log screenshots the small compactions are taking ~20s and the first one listed took a very long time, I think maybe your disks backing this may be very slow? Like, overlayfs slow (storing the files within a running container). Just a guess there, though.