Hi @meigallodixital,
We have the same requirements in France (Major compliance requirement for France due to the POS module).
Actually a lot of issues regarding immutability and stock adjustments could maybe be handled by not authorizing to use the POS offline (could be an administrator switch maybe ?)
A lot of complexity is due to the offline functionality and currently the POS is not compliant with a few countries’ legislation.
There are some discussions on GitHub, don’t hesitate to participate 
https://github.com/frappe/erpnext/issues/7582