Deploy custom extension-only app to multiple non-plus shops

[MichielfromNL]

We run several shops but Plus is still way too expensive for us.

We wrote a small checkout validation on addresses, to limit non-deliverables and returns for customers that forget to enter details etc. Good for the environment 🙂
But we are running into the custom app distribution limitation : our custom app can not be deployed to multiple shops, because that is apparently only available to PLUS merchants. Tried it just to be sure: the install link  indeed only works for 1 shop for which the distribution is configured.

The remedy for us is to replicate our apps with each slightly different names for each shop . Which consequently requires the synchronization of code updates across multiple instances of essentially the same app, multiple deployments and updates, etc. 
Anyone any ideas on a better approach ?

And dear Shopify, checkout validation lowers the volume of  returns and contributes to sustaibability policies So why don't you lift that restriction and allow non-plus merchants to deploy these small improvements to multiple sites? Or perhaps come up with a seperate , more modest fee for use of UI-extension and multiple deployments?

[jorhan]

This is a good problem to solve as we don't have control over Shopify limitations. However, I would suggest using just one code base and using Nginx to handle different subdomains but point to the same services. Hope this help save some hassle. 

[MichielfromNL]

After some experimentation I found a relatively easy solution myself:
Since this is an extension-only app, the extension is identical between each app for each domain/shop, i.e. does not have any data relating to the specific app (name).
So simple symlinks to include one extension directory/code base in Vscode did the job , we make it generic with API keys per domain and localization, and the only thing we then need to do multiple times is to run deploy  for each app .
Hope this helps other developers running into the same problem!