Hi Dimitris,
Migration of configuration changes between Sandbox and Production has always been a bit challenging, especially with the Modern UX. OOTB, we provide the Content Migration Packages which can handle some of the migration changes (Objects, lookups, etc), primarily for the Classic UI:
https://techdocs.broadcom.com/us/en/ca-enterprise-software/business-management/clarity-project-and-portfolio-management-ppm-on-premise/16-3-2/reference/clarity-ppm-studio-development/clarity-ppm-studio-content-packages.html
For other items, you will need to rely on our older WSDL API - the XML Object Gateway (XOG). WIth XOG, you can handle everything in the Classic UI that the Content Migration Packages do not cover, such as users, security groups and everything else.
https://techdocs.broadcom.com/us/en/ca-enterprise-software/business-management/clarity-project-and-portfolio-management-ppm-on-premise/16-3-2/reference/xml-open-gateway-xog-development.html
For the MUX configuration changes, you will need to either do them manually or look to our network of partners. If you Google "Clarity Content Migrator" you will find some hits from our export advantage partners. These utilities can handle Blueprints, views, Field Level security, etc.
Regardless of how you do it, I highly recommend tracking a change log with the order in which to promote the changes to your environment as a best practice. One of the weaknesses of the content migration packages is that it blindly applies lookups, then objects, ect. In some scenarios, you need the object before the lookup, such as ones with object lookups or query based ones. For the content packages, you simply need to reapply the failed objects in the UI if you run into any such issues.
If you would like to see a unified solution for the management of content, I suggest joining our monthly innovation calls and supporting one of the ideas in the community.