There is yet another fundamental problem with this: It is absolutely possible to hold trials for people where some of the evidence is classified. The US does it all the time. The system that was set up for it post-9/11 is sorta bullshit, stacked in favor of the government to an almost unbelievable degree, but it does function well enough that the more authoritarian elements have been moaning about how horrible and unfair it is that they have to deal with the FISA courts instead of just "do what I say to this poor helpless person, because I am king."
Of course, now it's all ICE, so they're bypassing the courts entirely. But for over twenty years we were running semi-due-process trials that included secret information as evidence, for this exact reason.
I saw an ad on YouTube for what a good job ICE is doing not that long ago. Kristi Noem was in it.
More disturbingly, I've noticed a little scattering of those "police bodycam raw video" channels starting to play up when the criminal involved is an immigrant, what their status was, how ICE was involved, and so on. There's clearly something at work that's a little more subtle and sinister than just paid advertising.