.wp-block-button__link {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    overflow: hidden; /* Prevent shifts */
}

/* normal text */
.wp-block-button__link .button-normal-text {
    display: inline-block;
    transition: opacity .25s ease;
}

/* hover text (hidden by default) */
.wp-block-button__link .button-hover-text {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    opacity: 0;
    white-space: nowrap;
    transition: opacity .25s ease;
	visibility:hidden;
}

/* show hover text & hide normal text */
.wp-block-button__link:hover .button-normal-text {
    opacity: 0;
}

.wp-block-button__link:hover .button-hover-text,
.wp-block-button__link:focus .button-hover-text{
    opacity: 1;
	visibility:visible;
}