Upgrade website from Joomla 3.10 to 4 or higher and PHP update to 8 or higher

I am looking for a skilled developer to upgrade my Joomla website from version 3.10 to version 4 or higher. Additionally, I need the PHP version to be updated to version 8 or higher.

Current Version: Joomla 3.10
Custom Extensions or Templates: Yes
Backup: Yes

Skills and Experience Required:
- Strong experience with Joomla and PHP
- Expertise in upgrading Joomla websites to newer versions
- Knowledge of PHP 8 and its compatibility with Joomla
- Experience with custom extensions and templates in Joomla
- Ability to handle backup and restore processes during the upgrade

Please provide examples of previous Joomla upgrade projects and any relevant certifications.