7.4 just ended its security support so you might argue that you should be at least on 8.0 just in case a bug is found and not backported.
Truth is: it's not likely.
But in any case theres no need whatsoever to use the latest version and even less when you are using WordPress which is notoriously bad at keeping up with PHP releases.
PHP 8 is in "beta support" currently, but that's just Core. A lot of plugin developers are lightyears behind it seems:
https://make.wordpress.org/core/handbook/references/php-comp...
WP Core is absolutely compatible. Its the themes, plugins and custom code (usually in functions.php) that isn't.
> but that's just Core. A lot of plugin developers are lightyears behind it seems.