Hi there,

Yes, you can host multiple websites on the same server. You would have root access meaning that you will have full control over your server configuration. Here is a step by step video on how to add a second site to the One-Click WordPress installation image:

The speed between Litespeed and Apache is debatable. Usually, it is said that Litespeed has better performance than Apache, but if you follow some best practices the difference should not be noticeable:

https://www.digitalocean.com/community/tutorials/how-to-optimize-wordpress-on-ubuntu-20-04

Regarding security, the 1-Click installation already comes with Fail2ban pre-configured. What you could also do is sign up for a free Cloudflare account which comes with free DDoS protection and also could help you with your website performance.

On the security topic, I could also suggest following the steps from the answer here on some really good tips on how to secure WordPress:

https://www.digitalocean.com/community/questions/how-to-secure-wordpress-without-a-security-plugin

Hope that this helps!
Regards,
Bobby