This CSS snippet fixes the Discord Server Banner gradient size, and also fixes the banner size on Visual Refresh Experiment.
/* Fix server banner gradient and size */
.visual-refresh [class^=animatedContainer_] [class^=bannerImage_] > img {
width: calc(var(--custom-guild-sidebar-width) - 32%);
}
.visual-refresh [class^=animatedContainer_] [class^=bannerImage_]::before {
width: calc(var(--custom-guild-sidebar-width) - 32%);
}```
Screenshots: (before/after)