Is anyone here working with Filament while using a heavily custom UI for it?

It's generally not been recommended to customise the components directly to my understanding - makes updates difficult.

I'd really like to advocate for Filament going forward at my new role, but the biggest barrier is corporate requirements to use a specific UI/Design language, even for web apps that ostensibly would be much better served by being built with Filament rather than by hand with something else.

I'm looking for anecdata on difficulty/ease if building & maintaining with more custom UIs.