Hello Zim,
Meta Box doesn't support an option to style the form fields. You need to create your own custom CSS code to style the form fields. If you want to enqueue your style file, please follow the documentation https://docs.metabox.io/actions/rwmb-enqueue-scripts/
And does it matter or not for example if I use Bricks Builder.
I'm not sure if the builder has its own style that affects the HTML input tag of the field. You can contact Bricks support to get more information.
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