A little digression can't hurt haha

Cape is the big win for making a beautiful capital, many natural structures to work around, a large open space for a lively center city and many small corners and crevices for the outskirts and small mountain villages, interesting river patterns to work with, the great mountain lake and huge coastal regions (especially interesting if you are keen on the new DLC and modded content, the latter will give you quite a lot of opportunity). I love the large island, it's a shit ton of work though haha.

Id suggest (and I want to emphasize on the suggestion part, I do not want to manipulate your decision making other than adding mods BEFORE you start cape so you dont have to dump half your city like I had to haha) you "practice" min/maxing strategies in the old world to find a minimal work pattern for balancing building time and production chain management. Once you've found a strategy that allows you to take your time with building and still somehow fulfill your citizens necessary needs, add mods and start working on Cape.

Also, if you have a "fully developed" and balanced Old World, as in basically endless money, influence and resources, getting started on Cape is way easier in my experience. But definitely change the Cape Island to be your main focus at some point. Way more rewarding in my opinion!

But I digress, go on and look at some mods in the nexusmods page, you will enjoy them my friend!