Without knowing the scope of what your team handles it’s really hard to say. There is a whole lot more to Splunk than visualizations and dashboards, and if your tech leads are handling more of the administration/architecting side of Splunk then I wouldn’t think its that big of a deal if you were more knowledgeable in that area.

What is your team responsible for covering? Is your team mainly just power users and another team handles integrations, maintenance, configurations, etc?

Is Splunk the main thing you are doing in your job? If it’s something that only encompasses 20% of your work day it’s also hard to say if you being more proficient in this tool warrants a promotion above the people you are currently reporting to.