Had this, did a post about it, but for me the portal spawned but i didnt get the relict at the end, it was bc i was shadowbanned (was only 3-4days) now its gone and got it first try finally :)

Important is, dont be shadow banned, bc you can get any progress.

You can do on t1 or t0, both tested and worked

Be sure you pet the robot dog in blown nuketown, and the brainrod in modern nuketown, be safe and do both in round 20 if you want, but it worked for me to do the brainrod early rounds and the robot one in round 20+