Employees on their own time, or paid to do it?
So I'm clear though - if I wrote a SAAS product tomorrow that under the covers used Redis, I'm OK, but if I spun up a bunch of servers and offered managed Redis as a product, I would need to pay?
That's the pitch of the license, essentially, but in practice the SSPL is an utter nightmare to comply with (to the point of being deliberate) and it mainly exists to put a veneer of open source on a proprietary product. In actual practice you really just cannot offer Redis as a service unless you are Redis Ltd, which is the actual point of the license in the end.
Isn’t this exactly what the person you’re replying to was saying?
You should probably ask Redis, Inc. what their intention is. Keep in mind, though, the run the risk of being re-rug-pulled. They have changed the license once and they can do it again.