extend our current app to subdomains Laravel/MySQL/VueJS

We have an app (created in Laravel and MySQL). This app was designed for our organization. Now we need to make it available to our concurrents also. So, we need to make an infrastructure, in which we can offer companyA.domain.com and companyB.domain.com. Where the functionality of both subdomains comes from one base architecture.

-> Content (e.g. what's written in the Database) not copying, functionality
-> one codebase. Need to work/maintain from one codebase. No extra coding in any of the subdomain applications
-> Admin dashboard
→ Admin can create new subdomain (e.g. data.domain.com, 2striped.domain.com)
→ Admin need to make database (fully secured database with all the necessary tables)
→ Any other tools etc which are in the app, need to be in the subdomain as well
→ health checks of the database, subdomain and any other errors are reported here

We host our VPS’s
Need to make
-> Every VPS will have to share 3-4 clients
-> In the admin dashboard you will see how many clients are connected on each VPS
-> When limit of 3-4 is reached, automatic deployment need to be of another VPS, where the codebase is also shared to and the application can run further

Fixed fee of $1000