Hi. There is no way to correctly configure this, except for the use of CSS.
.my-count .sppb-countdown-timer {
display: grid;
grid-template-columns: repeat(4, 1fr);
}
.my-count .sppb-countdown-timer.sppb-row > div {
max-width: 100%;
padding: 0;
}
.my-count .sppb-countdown-number {
display: block;
width: 100% !important;
}

In the addon settings, use only height option. Width option will not work after using this CSS code.
The remaining things, like background and border radius, you can configure through the addon's settings.