This article is based around the question of whether a Splunk upgrade influences search performance, and trying to determine how much difference the upgrade itself makes in terms of search runtime.
The full post is available on medium as Splunk SHC Upgrade Performance — Comparing search runtime from 9.3.3 to 10.2.5. A Splunk lantern version is available as Comparing search performance before and after a Splunk platform version upgrade.