How would you design record access for an org where sales reps see only their own opportunities, managers see their teams', and a small deal desk sees everything?

I would set the Opportunity organization-wide default to Private, which gives reps their own records. The role hierarchy then covers the managers automatically — that is precisely what it exists for, and it needs no configuration beyond a correct hierarchy.

For the deal desk I would ask how many people and how stable the population is. For a small, stable group I would grant View All on Opportunity through a dedicated permission set. It is one object-scoped permission rather than a sharing rule that has to be maintained, and it is honest about what is being granted.

I would specifically avoid two things: putting the deal desk at the top of the role hierarchy, which grants far more than opportunities and distorts forecasting, and granting View All Data, which is org-wide and unnecessary.

I would also ask whether opportunity teams are needed for the supporting cast — sales engineers, legal — because that is a per-record requirement the hierarchy cannot express.