Investments for GC, similar to ritual mechanic

KDs often exit war and have an abundance of extra gc, especially as science and the ability to overclock rituals come in to play. It would be an interesting addition to the game to allow either individual provinces, or KDs as a whole to invest their gc into a buff, similar to a ritual. I am not particularly fond of how finding plunder targets via war tracking tools has become so easy, so an option for GC investment might offset the inevitable vulturing that KDs face when exiting eowcf.

I have some ideas for what these KD wide investments might look like besides a KD wide bank account that pays interest out to each province. For balance, only one should be available at a time with mechanics similar to ritual. I have no idea what they should cost and/or if they should have different costs or different effect duration. Overall though, I think it would be cool to have another avenue to utilize Gold in and outside of war other than Dragons.

Investments

Sow the Fields
Purchase better tools for your peasants in the fields, increase Food yield by 30% for 1 year.

Ludi
Your Kingdom holds public games for all to celebrate the wealth of their lords. Increase Max Population 5% and Birth Rate 15% for 1 year.

Roads and Aqueducts
Build paved roads and raised aqueducts between your Kingdom's provinces. Increase Income 15% and Reduce trade tax by 75% for 1 year.

Hire Condottieri
Purchase professional soldiers from your neighbors. Provides each province with 2% of their max population in soldiers and specialist credits.

Build a Wonder
Show your Kingdom's strength by constructing a Wonder for the World to behold. Grants 20% of land in building credits and decreases construction time by 25% for 1 month.

Reinforce the Ramparts
Your Kingdom constructs additional barriers to dismay would be attackers. 10% lower resource losses when attacked and decrease defensive military casualties by 10% for 3 months.

Iron Forges
Your Kingdom's blacksmiths find a better way to forge. Increase enemy casualties by 10% for 3 months.

Barding
Outfit your War Horses with Protective Body Armour. Increase War Horse attack strength by 1(2 to 3 points) for 3 months.

I do like the idea of 'Kingdom Projects', or something of that nature.

Something like this does already exist; The Wall. It has a tick-by-tick cost though, as opposed to large bulk investment.

You could have them draw on all other units of the economy; gold, food, and soldiers. Some projects may only incur one type of resource cost, others could involved all three, depending on the context.

I think I would prefer this method(tick-tick cost), as it would make it necessary to plan your projects ahead of time. As opposed to coming to the end of your CF, realizing you didn't draft in a timely manner and hide all your GC into a project. No.

1YR effect-length may be a bit long for this approach.

I would break that 1YR into halves; Once you 'activate' a Project, your KD is committed to tick-tick costs for the next 84 ticks- this cannot be cancelled, and the costs are skimmed from your province each tick as a % of your gross production(Some projects may even have to force a minimum draft rate, or lock it in, as in protection). After first 84 ticks your Project is up, and begins to decay.

Sounds like we've come full circle to buying sci with gc again! Which was interestingly removed because the randbobs were angry the top kds always had too much gold to spend on it.

Instead of ritual mechanic it could be like the dragon but for your own KD. A Warden that gives bonuses and is weaken by outside attacks only(defensive casualties weaken it).