It’s probably not only your browser. But it may be a only subset of browsers - what’s happening on my browser is that it’s loading the Inter font for the non-special characters, but falling back to a different font for your accented characters. Which is why things look weird.
From looking at the source code for your page, it looks like the font is loading here:
@font-face{font-display:swap;font-family:Inter;font-style:normal;font-weight:100 900;src:url(../fonts/inter-roman.woff2) format("woff2")
That’s loading the font from within the theme, but that version of the font looks like it’s missing some characters. Instead, try this in your code injection header (access through /ghost > settings (the gear icon) > code injection:
<style>
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@100..900&display=swap');
</style>
edit: I thought I’d opened a bug on this issue, but I don’t see it. Will open one.