Big Update (IME only):
Fix for all all playable factions starting at tier 3 besides some minor settlements.
Adjusting partially Province ownership at start of the game, being very related to radious.
Complete overhaul for all starting buildings (mostly only human player) + works both vanilla and with radious.
Reason behind those adjustments are that factions in general are able to be played at this difficulty from the very beginning, and starting upfront with only tier 1 units is very questionable like it was partly beforehand.

Every faction starts now with sometimes multiple tier 2 buildings offering tier 2 units, besides like exception of boris for example starting with rather "weaker" tier 3 units especially in radious, which feels more fair to me with having a quiet bad spawn and only 1 minor settlement. I also added mostly growth buildings sometimes additional economic buildings aswell. Some factions also got lore and/or theme and/or balanced based tech buildings which races do not often offer (at tier2) . An good example is the tier 2 siege workshop for dwars here , or tier 2 beasts for lizards.

If you notice anything unusual let me know, creating this took actualy days of my time for getting stuff to work especially because its very conflicting with radious sometimes, its quiet a lot of scripting and mistakes can happen.

Since all playable factions (LL) start now at tier 3 and the others do not, it is to be expected that those are gonna be even more dominant now thus defeating other none playable AI factions even more easily while being harder to be beaten itself. The higher tier start is gonna get them sooner access to better units while their settlements are also sooner stronger in defence, so also for you as the player, playable factions are not the easiest targets to eliminate.

In terms of coop as Im aware of how it used to work in Warhammer 2, building changes for most of the times will work only for the hosts faction. The reason behind this is, that otherwise changes would apply to all the AI factions aswell in any campaign, which makes the hardest part of the campaign even a lot harder, which is obviously the beginning.
Furthermore Warhammer 3 suffers a lot on desync, which worsens by radious and this mod on top. The increase chance of desync is based on the lower upkeep of radious thus leading to more armies populating the map and here additionaly based on boosted AI economics and recruitment speed. If you realy want to try anyway (coop), I recommend you a heavy upkeep increasing mod, there is also one from radious increasing upkeep by 80%.

Added another table helping possibly war declerations, deleted tier 3 for captured settlements --> makes campaign to easy

equalized expasionism from AI and Human Player, increased expansionism by a bit in total, decisions were made on player feedback

Final Update for now, I added in the recent days tons of content and was for most of the day working on the mod. I might get some new ideas in the meantime, but overall next patches will be rather about fine tuning, feedback especially in unusual behaviour of the AI or wrong behavious is very appreciated!