The docs should change https://www.mongodb.com/docs/manual/reference/sbe/#eligible-queries-for-the-slot-based-execution-engine. SBE is eligible only for $group and $lookup stages.

The $_internalUnpackBucket stage for timeseries also uses SBE, but that is an internal stage.

Description of Linked Ticket

As a follow up to SERVER-83470, make the new knob the default behavior. 

Additional Notes

Per christopher.harris@mongodb.com, we might want to rework the eligible queries section to be more vague, as the queries are prone to changing release to release, and we run the risk of showing outdated / incorrect information. Please include Chris on the review for this update.