SSPL has no provision even close to the reach of the "anti-competition" clause Hashicorp is using. While SSPL is not considered open source, it isn't that far off from the AGPL. The difference between SSPL and AGPL is that SSPL (1) is in effect regardless of modification of the service and (2) extends copy left virality to all programs which support running the service, including those that interact with the software over a network.

MongoDB, Elastic, etc. cannot stop you from running a competitor based on the terms of their licenses, they just ask that you publish the source code for whatever service you're running in its entirety (I acknowledge there are disagreements about how far "entirety" extends). The clause in Hashicorp's license actually revokes the right to use their software at all if you're a direct competitor.

OK, no one is going to build an open source competitor to Elastic or MongoDB because then you have no moat and your business will probably fail, I get it, but it's still possible to do without repercussion. It's not like the AGPL is that far off in terms of limitation, either, which is why you don't see many copyleft services run by large corporations unless they've been dual-licensed.