Website fails when PHP is updated

I am seeking a skilled developer to address compatibility issues with my website, which was designed in 2020 and currently utilizes PHP 7.3. The recent update to PHP 8.3 has rendered several slider tools inoperable, compelling me to incur additional costs for continued support of the outdated version. I require a professional who can efficiently resolve these issues while ensuring the integrity of my existing website, bsi-dconsultancy.co.uk. Prompt assistance is essential to minimize disruption and enhance performance without compromising current functionality.