.blur-container {
  position: relative;  /* notwendig für ::before */
  z-index: 0;          /* Basis-Z-Index */
}

.blur-container::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  -webkit-backdrop-filter: blur(50px);
  backdrop-filter: blur(50px);
  z-index: 1;
}

.blur-container > .brxe-container {
  position: relative;
  z-index: 2;   /* Inhalt liegt über dem Blur */
}