What is my best option to get Groove Agent?

Hello. I am new to all this. but I’ve been using cubase 9.5 LE AI for a while. That version works fne for me.Now I would like to get a Groove Agent. 4 or 5 does not matter to me. Actually, it does in the sense that I would like my most economical option. I’ve also looked at upgrading my Cubase 9.5 LE AI to Essential, since it seems to include a version of Groove Agent…
First, I do not find an option to upgrade from LE AI to Essential, so I would have to purchase Essential, and as i understand I would not need to buy the USB licenser key (?). The oroblem is that I believe Cubase Elements 9.5 comes with a Groove Agent SE (? again I cannot clarify).
Second option would be to buy Groove Agent 4, which I believe requires a licenser USB key.
Third option is to buy Groove Agent 5, which (again ?) I believes does not need a USB licenser key.
Could someone please help me figure out my best option ?

Have you seen this option?