4) What is the difference between detaching and deleting an EBS volume?

Detaching EBS volume temporarily disconnect, Deleting EBS volume permanently terminate from AWS

5) What is the difference between gp2 and gp3 volumes?

gp2 is a general purpose SSD and gp2 is a general purpose SSD next generation

What are the best practices to secure data in a cloud server?

use strong encryption and implement identity and access management to secure data in a cloud server.

Can I use a mix of physical and other servers together?

yes, can mix physical (dedicated) and virtual (shared) servers together

Which server type offers the fastest performance?

dedicated host or bare metal server are the fastest performance server types.