Clients hand us material that is not public yet. Unbuilt schemes, sites that have not been announced, competition entries under embargo, drawings covered by an NDA. That is normal for this work, and it is the constraint everything else has to fit around.
Most AI tools work one way. You upload your material to a company's servers, their model runs there, and a result comes back. The terms are usually reasonable and the companies are usually serious. But a term is a promise about what someone intends to do with your material, not a fact about where your material is. Once the file has left the building, you are trusting a policy.
There is a second way to run a model, and it has only recently become practical at the quality this work needs. You download the model itself and run it on a computer you own. Nothing is uploaded, because there is nowhere to upload it to.