If this is a question then I did not get it.

This is a very cool mod but I'm curious and worried by disabling missions that I will be increasing the chance of Chosen/Ruler appearances on enabled missions.

Specifically for amubhses you don't need this mod: there's a base game config for mission familities that chosen cannot appear on. Ambushes are there by default. The reason I can't use this config for the purpose of this mod, is that the two targeted missions share mission family with other mission types on which chosens are ok.
Look for the "ExcludeChosenMissionSources" config in XComGameData.

Could I configure the ini in this mod to do the opposite? Like allowing Chosen to show up on ambush missions so I have a reason to be worried about ambushes?

on the mission types supported by this mod, Supply Extraction, and Recover Expedition, you should not get the Chosen spawning at all when using that mod.
You can add other missions to this list, but you'll have to do it yourself. If you do see the Chosen on a mission supported by this mod, then something is not working.

does this work out of the box so that no chosen spawn period or do i have to do brain surgery on the game to even get it to work like that

this is a base game sitrep. I think it used to be a GTS Unlock back in pre-wotc XCOM2.

which sitrep is that lightning strike one from?

For the base game missions, you can see it in the default config folders, under the DefaultMissionDefs.ini file.
For modded missions, you need the XComMissionDefs.ini file of the mod that adds this mission.

Is there a way to get a list of the specific "MissionName/sType parameter" of missions?

@lordabizi It was one of the Covert Infiltration supply crate missions.

Thank you for the report, I'll try and replicate this at some point.

@lordabizi I had the Warlock show up on a mission with a remote area sitrep. It was his first appearance.
Attached is my launch.log file. https://www.transfernow.net/dl/20230717vdwtwDUM

Using it uniformly is my intended use case.
Doing for individual rulers should be easy enough, check the configs in XComGameData - it lists all the tags which are excluded by the sitrep, so just remove those you don't want.
I don't think I plan to do anything more refined than that though.

@LordAbizi - Secondary question: is there intent or possibility to expand so settings may be created per individual ruler/chosen type, or is the intent that this should effect them all the same without individualisation? =)

Thank you for the clarification. As always, your work is much appreciated.

Infiltrations have their own logic to determine if Chosen or Rulers belong on them. For Chosen I can say for sure that this mod just won't do anything for them. For Infiltrations I'm not 100% sure, but this mod will either work or not, but the game shouldn't break.

Question in regard to CI: If a mission is added that is both an infiltration and an assault, does the ruler/chosen get removed from the assault based mission, but not the infiltration variant, or does the X2 engine meltdown and do strange, bizarre things?

This reader agrees with the previous reader, and also appreciates the author for making such amazing mods! But this reader will definitely read this carefully

The reader does not know if he really needs this, but wants to thank the author for making this.