Notably the risks aren’t simply that this will identify the undocumented its that it will provide a pretext to disappear almost anyone who isn’t white.

The question is does any given non-white person look enough like one of over 10M people to get falsely flagged given agents a pretext to remove almost anyone they stop. Facial recognition of one person against a large enough database will almost always provide at least on possible match this is especially true if it matches against possible aliens and not against possibly aliens and citizens. EG a query of both will likely turn up Betty Sue Smith is herself and maybe a possible match with Known Deportable but a search against only aliens may return only Known Deportable with agents dismissing any claim by Betty that her ID must be fake.

What do you think what you posted even means? covering most of what it is using to identify is already going to make it drastically more difficult to match