There can be several things that can impact your application. The first thing you'd want to do is review the PHP change logs. Start with 7.3 -> 7.4, then 7.4 -> 8, then all the 8.x versions.
https://www.php.net/manual/en/migration74.php
https://www.php.net/manual/en/migration80.php
https://www.php.net/manual/en/migration81.php
https://www.php.net/manual/en/migration82.php
Are you going to be upgrading your Laravel version as well? If so, then you'll want to review the Laravel migration guides.
Does your application have a lot of package dependencies? If you only have a few, upgrading will likely go easier. If you have many, then you might run into incompatibility or version constraint issues. You should check all your dependency packages to see if they support PHP 8.2.
Do you have test coverage for your app? If you do, then this will be less painful. Your tests will immediately provide feedback on anything that breaks. If you don't, then upgrading will be scarier for you. Regardless, it would be a good idea to try upgrading on a staging environment first, especially if you don't have any test coverage.
You could also look into Laravel Shift. I've never used it personally, but it has been around for a long time.
