I have been playing around with the potential tech stack, and after having been a .NET guy for years, I am leaning towards a Google Cloud Firestore for the datastorage options, .NET 5 backend apis, and Vue 3 for the frontend.
The dynamic storage solution in GCP is so awesome, and I love playing with it. The scalable and highly durable object storage is so simple to use and work with.
I have also been coming at this from a different angle than usual. Instead of creating a backend, api and datamodel, I am creating the point of sale widget first, playing with the datamodel from there, and will be adding the backend later. That way I can figure out the functionality from an end customers point of view and figure out the backend later.