(S) Player Retention End-Game 'Activity' (player safe-zone)

I get that there is Zana, blah F8 shift+turd about what is in the game already, but I don't think there are many things to do besides progress. I know Heist is a relatively new way to try to keep players around with something to do besides progress, but what if there was something else to do. Let's say a player is committed to staying at the level they are, what are their options for End-game activity? Before I mention the obvious in-game activity, let me point out that there may still be void left to fill. Now, the most obvious in-game no progress end-game activity is hideout decorating. Hideout decorating requires end-game Atlas farming to access tiers of decorations. There are hideouts that are hidden in Atlas that can be farmed for. This is a great end-game activity while trading. I mean, trading itself is a great end-game activity, but hideout decorating is the most solo self activity there is. With that being said, the best reason that the activity itself is great for end-game is that the player can't lose any progress on their character. They won't die while placing trees or building booba. It's this end-game Safe Zone that players seek.

But, what if there were timed League mechanics that can be distributed via a toggle or a new mechanic, altogether? A new safe-zone that requires end-game farming.

I wanted to suggest a couple of options.

Blight Waves Ladder

Both similar to Ultimatum, but safe-zoned (with the ability to toggle off safety) that requires players to complete waves to compete for end-game prizes or competitive gloating or friendly-competition. I get that Blighted Maps and Maps that contain a Blight Encounter have waves, but they're less interactive as Ultimatum and don't have a start to each wave. If a wave counter were added, rewards could be similarly 'chosen' but also similarly increasing in difficulty like Mine Encampment depth. I chose to use Blight as an example for it's main feature of Tower Defense. I feel that this mechanic is best suited for a ladder because of its random fungal lane construction and tower positioning.

I mostly wanted to emphasize that there isn't much to do in terms of End-Game Activities.

Thanks for your time.