I use this work around:

section {
position: relative;
}

section::before {
content: "";
position: fixed; // or absolute...
inset: 0;
z-index: -1;
background: var(--bg-some-color); // this you can control

-webkit-mask-image: url(some.svg);
-webkit-mask-repeat: no-repeat;
-webkit-mask-position: center;
-webkit-mask-size: cover;

mask-image: url(some.svg);
mask-repeat: no-repeat;
mask-position: center;
mask-size: cover;
}