Is it more performant to remove components from existing widgets than to create custom widgets?

I am making a Flutter desktop application that uses multiple widgets for example like 30 to 50+ buttons (or any interactable widget) on a single page/screen.

I don't want the default styling of Flutter like the InkWell in ElevatedButton, etc. I want to have custom styling.

Screenshot - my application is similar to this:

As you can see the widgets are heavily styled (probably even more styled than shown).

Should I create custom widgets from scratch, for example starting with a Label, adding a rectangle around it, etc? (oversimplified)

OR

Should I use Flutter widgets and style them, remove the inkwell effect, or anything I don't need from it?

For anyone concerned, I don't mean I will style each individual element, I will still make a widget customizing the Flutter widget since repeating this for multiple buttons will not be feasible.

My main concern here is performance. I want this app to be fast and cross-platform.

Is it more performant to remove components from existing widgets than to create custom widgets on a large scale?

From this week's Observable Flutter, I learned of https://pub.dev/packages/mix, which might be at least part of your solution.