
Helldivers 2 developer Arrowhead has suggested it plans to add a test server to the game at some point.
Test servers are fairly common in online games; Diablo 4 for instance got its first public test realm (PTR) with Season 5, allowing Blizzard to run test updates for folks on the PTR to try out before anything's made official. Developers typically use feedback from those trial runs to make targeted changes before releasing updates into the main servers that everyone plays on.