If this is something you are going to attempt yourself, essentially you will be doing the following
Backup, backup, then backup some more
Remove all 3rd party items that you are not 100% using
The ones that are left, you need to contact the authors to see what to do with them. Thi sisnt really something we can advise on. Generally it would just be to disable them and then upgrade them once you have upgraded the software, but best practice would be to contact the author
Switch the site offline from your admin CP
Change your PHP settings to run PHP 8.1
Run the requirement checker to make sure you have everything updated you need to on your server
Upload a fresh set of files from your client area
Run the upgrader from /admin/upgrade