Love the premise of June. Just signed up.
Re Scrum, it’s an agile project management framework and you are free to adopt parts, or in whole, as you see fit. It does not purport to solve everything and it has known gaps, but it is also not prescriptive. I agree that computing velocity is an exercise in futility.
Having said all that, I still think that Scrum is an awesome framework to start with. There are no better alternatives to the crummy waterfall methodology, IMO. I would suggest that an organization new to agile frameworks, starts off with implementing Scrum as it defined today and look to make improvements in the process as they see fit over time.
Some companies simply use a Kanban board to manage their development effort. Whatever blows your hair back — anything really but please keep away from SAFe, scaled agile and other bastardized variants thereof attempting to take us back into the dark ages. :)