I've been there since the 00s and I can say that no "alt-tech" options would allow 4chan migrants to act like well 4chan migrants. The BirdHarvest site is basically the only one, and its still non-anon.

Every time one of these "options" crop up, you can just pose a question or two and watch them immediately reveal how quick they'd sell you all out. The "loli" one is an age old barometer and works almost every time to show that even if its not something you like, their "principles" are always easily dashed when they get emotionally or disgusted by something.

However this is talking under the assumption that 4chan is some monolithic thing, instead of dozens of boards with minimal interaction with each other and far different sensibilities.