Try out sharry. Sharry is a self-hosted file sharing web application.
It works pretty well for my use cases. I also like the alias feature, what is pretty much what you are searching for. The only thing I miss, is the possibility to download a share as a zip folder. But there is an open issue for it, so maybe it will be added in future (again).
I am not an expert, but chat control and interoperable protocols are two different things, aren’t they? With stopping chat control you wouldn’t stop the law that’s restricting signal’s e2e-problem.
Edit: As far as I can tell after searching a bit, interoperable protocols will be requiered by the DMA, but only for plattforms. So you seem to be right, that chat control will be the big jeopardy for smaller ones like signal.