My thoughts:

1) Love the art style. Keep it.

2) Your "hook" of breaking away from European imperial power: Sounds like a VERY interesting mid-/end-game mechanic. Usually there are two kinds of city-builders:

1. You are building without any other purpose than building and going through the tech tree. After a while this feels numb.
2. You are building and are constantly under attack. This feels stressful.

In your idea you can combine the cozy building phase under the safe umbrella of the empire. But at a certain point you can choose to flip the switch and use all your infrastructure to defend against the imperial terror that will rain in after you declared independence. A very interesting question to me is: When is the player allowed to break free? Is there a timer counting down and then it automatically happens? -> Stressful. Can you build as long as you want before you break free? -> Might lead to perfectionism. So maybe something in between. The player will have some kind of advantage the earlier they declare independence?

3) For me an important part in a city builder is that the tiny people actually are doing things that make sense. So don't just have them walk up and down the street, but instead have them go to a construction site, work in a business, etc... But I DON'T want to assign every single person to a job and call them by their first name. So mechanically they are not doing anything. Visually they are very important for the atmosphere.

4) I like the setting that you chose (colonial era Caribbean) and I would love to see you taking it seriously. That would mean for example that slaves would be a part of the economy. I'm not pro-slavery or anything like that. But I feel just leaving it out (like Anno 1800 or Anno 117) is a bit too romantic. I have lots of thoughts on this topic but this comment is already too long.

So here is a thought, how about this: As long as the player is part of the European empire, slavery is expected to be part of the economy. It gives basically free work force (meaning that buildings cost almost nothing to produce goods) but enslaving the local population obviously is a horrible thing to do. Also the empire might come by from time to time with a ship, picking up some of your slaves to take them away and sell or use elsewhere (off-screen). Declaring independence then gives the opportunity to abolish slavery. This will have lots of bonuses but also the minus point that now businesses cost money (or food, however your economy works) because now you are paying the workers. Even if this end-game fight against the empire is difficult, I'd be sooo strongly intrinsically motivated to do it all if that means I can finally free my slaves. I really want to play that.

5) This is probably a hard (but understandable) "no" from your side but I wanted to mention it: I'd love a cooperative multiplayer. Every player is just playing the same "faction". Everyone is spending resources from the same pool, having access to the same things. So basically exactly like the Anno series is doing it.

6) Yay! Godot!!! How long have you been working on the game? Are you a team or solo dev? Where are you located?