Sub-domains and themes in multisite

Many thanks in advance for guidance.

Have a site that works well and now want to deploy it to others with the same look and feel.

Each subdomain will only see local data related to the topic covered by the subdomain.

Assuming the primary domain was called example.com them my two subdomains are

red.example.com
yellow.example.com

The theme I am using has a Primary-Theme as well as a Child-theme

Have enabled multisite and I can see the subdomain and logged into it.

I had expected to see the themes from the parent site being available within the subdomain but alas they are not showing.

Should I just install the both theme elements again into the subdomain? It’s the same project so licence is OK

Thanks
Paul