Is there a chance we get a sandbox/training simulator?

Lately I've seen a lot of posts and comments with the topic "builds against illuminates and/or harvesters" and it seems like a testing range could help especially newer players and the playerbase in general alot. Some kind of arena-style environment where you could spawn single or multiple selected enemies to test out new tactics, strategem combos and weapon loadouts.

Personally I'm Lvl 140 ish, so I don't really need it anymore but in the beginning it definitely would've helped against more difficult enemies.

There's a difference if you attempt to take down for example an isolated harvester in a sandbox environment to figure out its weaknesses compared to a regular mission with hundreds of voteless charging towards you and swarms of overseers whirring around your head. Plus your teammates are trying to kill it as well, so what actually did the job in the end becomes even harder to tell.

Effectively you need a couple of missions just to validate one good loadout, well IF it's a good loadout.

Or did Arrowhead already reject that option in the past at some point? (might have missed it)

PS: RIP Angels Venture