We'll need a bit more information than this to help you. Did you get an error message when you installed the update? Do you get an error message now?
If you get a Class Not Found error delete the file administrator/cache/autoload_psr4.php. It will be regenerated in the next page load. Joomla is supposed to do that whenever you install an update but sometimes (very infrequently!) it might fail to do that, leading to the aforementioned error. I had warned about that a few years ago when Joomla 4 was still in development but I guess the maintainers didn't believe me that it'd really be an issue. To be fair, it's a very rare issue to happen but when it does the error message and the solution are so far removed from each other that you need someone who's pored over the Joomla core code to make the link for you.
If it's a different error please let me know so I can better help you.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!