JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Какой-то заголовок&#8239;</h1>

CSS

h1 {
    display: table-row;
    white-space: nowrap;
}

h1:after {
    content: "";
    border-bottom: 1px solid;
    width: 100%;
    display: table-cell;
    position: relative;
    bottom: 8px;
}