What you do is wait for properly developed pads and avoid ones that are custom cut.
I know it's a pain sometimes to wait for aftermarket companies to develop new products, but this shows the risk you take when using modified and/or custom parts.
The best thing to do is voice your interest to the pad manufacturers, and have everyone else you know do it as well. Maybe start a thread asking everyone who will want aftermarket pads to post their response and mention a brand they prefer. Once you have a thread that is long enough, send that to the pad manufacturer(s) as sort of a "petition" to request properly developed options.
The use of any OEM developed brake package, even with aftermarket pads/fluid/lines, & no matter how "high performance" BMW claims the car to be, will always have a limit for full track use, BUT the ceramic inserts are NOT the weak link. Brembo has been using that same insert material and design with Porsche for many years now including their Cup Car applications for their intended race series.