How to maximize cache performance in Unbound DNS

[ensnare]

Running DNS Resolver (unbound) in my home lab, and I'm trying to figure out how to maximize the cache performance (minimize latency) for queries from local machines.

No matter what I adjust, there doesn't seem to be any impact on cache and reduction in latency. I am testing with namebench from a client machine. Even on repeat runs of namebench, the latency is the same -- shouldn't the cache be kicking in more?

I've tried switching to forwarding mode to improve response times without any change. I've also tried disabling DNSSEC and DNS over TLS -- no change.

Here are the latest settings. Any suggestions? Note: the DNS performance is fine, but this is a homelab and I'd like to optimize: at least beat the latencies of the forwarding servers for more of the cached queries.

Here's a latency curve taken on run #3