Hello & thanks for your work!
This feedback is based on following settings:
Galaxy Size: Small
Difficulty: Grand Admiral
Aggresivness: High
Regular Empires only so far
First things first:
Game Speed/Performance -> wow, i don't know what you did, but my game speed at fastest is around 3 times as fast than before! Good Job!
UI/Job/Building Descriptions -> clean, i like t!
AI: Despite my best affords to tech rush the AI into oblivion, it managed to stay on equivalent tech until the mid-late game, seems good!
Empire Size:
I was afraid that at some point expanding would feel like a negative, but that absolutly wasnt the case. Right now, its just a number in the background, nothing to really interact with, but thats fine as it's purpose is to slow down snowballing (numbers seem a bit low though and also seems to empathize pops in comparison to size a lot, which makes it so tall empires in comparison to wide empires get taxed by this almost the same amount (pops is power, for tall & wide empres alike). So right now, i dont think it rewards small empires enough and boils down to a background number slowing down your snowballing without any real options to interact with it.
Unity:
Unity from Factions: Insignificant -> a happy faction produces around 6 Unity more than an unhappy one, which is around 3/4 of a job and thats basicly nothing
Unity from Jobs -> Job balance seems to be off: Bureaucrats are terrible, 4 Unity for 2 CG is clerk level of bad, compare that to the manager of a Megacorp: same unity, same cg & added trade value, and even this job is borderline bad. An unemployed luxuary communist is more productive than that

For me i tried to get Unity the same way as before: make use of your ruler jobs & trade value and ignore all other unity producing jobs, because the numbers simply aren't there. Which brings me to:
Trade Value:
Ayyy, you truely didnt do yourself a favor by adding trade value (balancing wise ^^)
After nerfing merchants (added 2 CG upkeep) they aren't as broken as before, but are still good without trade leauge, and busted with trade league (the increased significants of unity kinda outweights the halved unity production)
Megacorps & empires focusing on trade value feels very wierd to play because of trade league -> being in a federation increases your effective trade value by over 100%, its not a choice anymore, its mandatory. (as is mercantile as first tradition into diplomacy) If you manage to get a federation within 20 years (very doable) you will rush through traditions and have enough Unity for everything you want. If you dont... well... you have an empire with effectivly -50% output on their most important ressource, and you might have to employ some of the (terrible) unty jobs.
Influence:
Influence is in a strange spot now - it gets used for early expansion, diplomacy, war and later habitats & megastrucktures. Some empires barely have anything to do wth influence - a non-void dweller, non warlike nation won't have any use for it, after the early expansion phase (considering diplomacy is an upkeep, not a cost). Here is a nice option though: wide empires have a lot of use for influence, tall empires don't - which brings me to:
Planetary Unity Upgrade (Ascension Tier)
Uff.... its yet another button in a game with a lot... of... buttons

I think it should cost influence instead of Unity to give tall empires a use for influence, other than that... its yet another pretty boring micro managing option, without a real decision: you upgrade, once the benefits of production are greater than the benefits of the potential tradition unlock. If it costs influence, it can be the decision between expanding (with force or otherwise) or upgrading, but even then, its just another bland modifier -> maybe make it a bit more flashy? (like giving a few super special ethic/designation-defined jobs instead)
Edicts
Oh my, Edict fund, edict cost, Unity upkeep, Energy upkeep, Empire size modifier - isn't that a bit ecessive? ^^
Maybe focus on the primary decision you want to give the players with these tools, because right now its a seemingly complex system of different modifiers & terms where in the end, all you do is choose the best modifiers (for your empire) from a list of different modifiers.
Balance Side Notes:
The 1% production on enforcers doesnt change their use: Only worth a pop on big planets (something you have to micro-manage)
Monuments are strange, i dont like them at all. so one building slot for (until mid game) less output than one of the worst jobs in the game. Still better than an empty building slot, but i thnk you can delete it without the game losing anything: if you want more unity you should need to build unity jobs, wich need pops & upkeep, like every other complex resource.
Void Dwellers start with Entertainer Jobs - please dont, you wont need them for a long time
Final Notes: I think the overall direction is very good, Empire Size modifier will definatly "feel" bad for a while, because we are used to not having them, but just like the pop growth sealing its a necessary step to slow down snowballing - i think they even are a bit to conservative - being bigger still makes you so much stronger & stronger faster
Unity & Influence -> Unity specialist jobs - most of all the bureaucrats are aweful (in comparison to rulers/trade value), factions feel insignifanct (and are in a wierd place in general), unity costs of leader is only significant in the early game (and feel restrictive when significant), and the most important use of unity is still traditons.
Leaders, Edicts & Planetary Ascensions feel a bit bloated - they dont give you much to play with, but a lot to think about.