I think the idea proposed by GoneFishingX of giving +50% production of national wonders to the civic nationhood is very good.
Of all the civics available, the one that would fit the most, even by its name, with this skill would be precisely nationhood.
And this would be good to give it a buff because, really, if the draft skill is not used/needed, this Territory civic becomes very weak, it only gives some happiness in some buildings, the effect of increasing the production of national wonders would be very fitting.
Maybe you could even adopt the idea of +1 happiness in cinema (Proposed by Hickman888), and maybe even +1 happiness in palace as well.
Another point I would like to talk about is about the civic Secularism, it became very weak compared to what it was in version 1.17. The fact that immigration does not bring religion helps to avoid problems with happiness, and this was a good change. But I think the +100% building speed for university building could come back, it would be very fitting for it.