Hey. So:

Hard crash: like I described, it happened at a specific date (reloading the save far back enough made the crash happen at a different date, but still happened reliably. eg crashing on 07/09/2390 reliably and then crashing on 10/11/2390 reliably instead. Since removing the mod made my game stop crashing and both marauder factions are dead, the only possibilities are the relic event or an event I don't know about with succesor factions.

Marauder faction completely broken: I had 2 marauder factions in my save. 1 awakened and worked well. The other one stopped working as if its AI had been disabled AFTER the 1st marauder faction awakened. They dissapeared from the contact menu, "closed borders" to me and could not be interacted with in any way. They had no leaders either. The way to get rid of them was to use console commands to play as them and delete their starbases so I could go kill their ships. The faction stopped doing any kind of events/raiding as well.

These were my mods:
{"name":"Zenith","mods":[{"displayName":"UI Overhaul Dynamic","enabled":true,"position":0,"steamId":"1623423360"},{"displayName":"The Zenith of Fallen Empires: Veteran Difficulty","enabled":true,"position":1,"steamId":"2478570992"},{"displayName":"The Zenith of Fallen Empires: Secrets of the Fallen Empires","enabled":true,"position":2,"steamId":"2087871245"},{"displayName":"The Zenith of Fallen Empires: Origins","enabled":true,"position":3,"steamId":"2492454618"},{"displayName":"The Zenith of Fallen Empires: Hard Difficulty","enabled":false,"position":4,"steamId":"2687933826"},{"displayName":"The Zenith of Fallen Empires: Engineering Perfection","enabled":true,"position":5,"steamId":"2499124566"},{"displayName":"The Zenith of Fallen Empires: Automated Industries","enabled":true,"position":6,"steamId":"2062797756"},{"displayName":"The Zenith of Fallen Empires: ASB Patch","enabled":true,"position":7,"steamId":"2499363733"},{"displayName":"The Zenith of Fallen Empires 3.0","enabled":true,"position":8,"steamId":"2044599287"},{"displayName":"The Great Khan Expanded [3.5.☠]","enabled":false,"position":9,"steamId":"2508704523"},{"displayName":"Real Space 3.8","enabled":true,"position":10,"steamId":"937289339"},{"displayName":"Dynamic Mod Menu [3.5.*]","enabled":true,"position":11,"steamId":"2458024521"},{"displayName":"Amazing Space Battles","enabled":true,"position":12,"steamId":"1878473679"},{"displayName":"Aggressive Crisis Engine","enabled":true,"position":13,"steamId":"2268189539"},{"displayName":"A Deadly Tempest [3.5.☠]","enabled":true,"position":14,"steamId":"2028826064"},{"displayName":"!!!Universal Resource Patch [2.4+]","enabled":true,"position":15,"steamId":"1595876588"}]}