Powershell Empire passed out of active development in April 2019, in part due to the problem of defenses catching up with it:
"The original objective of the Empire project was to demonstrate the
post-exploitation capabilities of PowerShell and bring awareness to
PowerShell attacks used by (at the time) more advanced adversaries,"
said Chris Ross, one of Empire's lead developers.
"We feel that we've accomplished that objective and are proud to see
the security optics and improvements that have been provided by
Microsoft in the past few years; in addition to the increased focus
the EDR [Endpoint Detection and Response] community has placed on
PowerShell based attacks.
"With that in mind, the project's time has passed and newer frameworks
with better capabilities have been released," Ross added. "So it's
time to say farewell to Empire. We will not be updating or maintaining
the project any further."
As a high-profile attack tool, it received significant attention from defenders. Likewise, Metasploit is tracked by many tools and is prone to detection as a result. For these reasons, writing custom code is popular with attackers and Red Teams alike.
You will need to find more obscure C2 code, or write your own, if you want to evade detection.