Hi there,
What metrics are you using to test the speed?
What example URLs are you loading that you're seeing slow times for?
We'd expect a temporary slowdown as the Ezoic cache builds, but we'd need specifics from you about what you've done to test, what you've already done with troubleshooting, and what specifically you're looking to improve.
Otherwise, we'd suggest you use support.ezoic.com and community.ezoic.com to look up guides to increasing speeds and improving CoreWeb Vitals metrics.