we have one site with wordpress with heavy traffic with around 50K users visits can aaPnael can handle this.. server is good with ram and cpu .
As per my experience, aapanel have no issues on heavy load. i already tested 100k Visitors for 4 days. My server Configuration is 16 GB RAM Octa Core Dedicated Server.
apache or nginx
Tengine is works well too
Denyka Yes, Thanks for the update