.wp-block-video {
    max-width: 850px;
    width: 100%;
    aspect-ratio: 16/9;
    height: 100%;
    margin: 0 auto;
    display: block;
}

.editor-visual-editor {

    .wp-block-video {
        height: auto !important;

        video {
            height: auto;
            vertical-align: middle;
            width: 100%;
            aspect-ratio: 16/9;
        }
    }
}