@nikuiz did you figure this out?
I am interested on a collection for Extreme BOSS (the ERS devices).
I can not find any until I saw this post of yours.
I was starting to gather information on how to extend the ansible.netcommon collection to build my own for Extreme BOSS but since it seams you already have something maybe you can share what you have we can work together on something.
I also saw this post (Accessing Extreme Network devices via CLI running on BOSS) from @Mittens66. Maybe he is interested also.