Put a gentle "Use Firefox" (or any other non-Chromium-based browser) message on your website. It doesn't have to be in-your-face, just something small.
I've taken my own advice and added it to my own website: https://geeklaunch.io/
(It only appears on Chromium-based browsers.)
We can slowly turn the tide, little by little.
<span id='browser' class='hidden'>
This website is designed for <a target="_blank" rel="noopener noreferrer" href="https://firefox.com/">Firefox</a>, a web browser that respects your privacy.
</span>
<script>
if (window.chrome) {
document.getElementById('browser').className = '';
}
</script>
Class .hidden must hide the element somehow, in this case I do: .hidden { display: none; }