Design and implementation of a dedicated IT system or CMS platform migration

I am looking for a person or company that can propose and implement a dedicated IT solution that meets the following requirements.

We are currently using the kodeksrodo.pl platform launched in March 2023. This platform was originally intended to replace the survey on Moodle and perform functions such as:

1. filling out surveys and generating certificates.

2. Presenting content according to the developed graphic design.

3. Providing users with individual accounts to access specific content.

The platform runs on CMS Joomla, but due to the large number of custom modifications, updating the system to newer versions has become problematic. As a result, we are considering two solutions:

1. Migration to a newer CMS (e.g., a newer version of Joomla or another CMS), with the possibility of adapting and expanding existing modules.

2. Creating a dedicated system designed from scratch, independent of the publicly available software.