usability – How to choose the general buttons of the dashboard when several customers have different colors?

I have this project, where I have to implement text, raised and ghost buttons depending on the different sections. It's a bit of a wizard-like application, with a dashboard with the steps to complete and submit.

So this application serves different customers, and with each customer, comes the main color which is the brand color of the same thing before. It is mainly used in the header of the application to generate a loyalty with the customer's brand.

There are exceptions, of course, like the colors of the icons. that is, the red for "caution," "error". or & # 39; delete & # 39 ;.

My question is, How to choose the color rules for the buttons when the customer's color may vary according to the occasion?

For example, what should I do when the main color of the client is red? (in terms of usability)
or in an extreme case, light yellow?

The bottom of the dashboard is white and light gray for the body.

Sample image:
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Thank you