Hello !
I can't wait for Drupal 10! This upgrade is an easy path with a tool like the rector module, it will check for any deprecations you might still have in your custom modules and themes.
Drupal 9.5 is the stepping stone for Drupal 10 and already has a stable CKEditor 5, this one being in my view the most impacting change (think of the CKEditor plugins). Make sure you can run PHP8.1+.
A pretty risk-free approach is to build your new website on D9.5 and test the upgrade to the latest D10 as part of your CI/CD chain.
Shall we organize a Drupal 10 release party in Geneva on the 14th of December?
Cheers,
Guillaume