

The only way to prove you aren’t homeless when out in public is to have an ID with your registered address.
If you go to a protest and you are stopped by police while you have ID they’ll register you as a target for later, if you lack an ID they could just insist you are homeless and throw you into a camp.
If you go to a protest and are stopped by police, regardless of that ID showing you have a home and you have any mental diagnosis (They now have access to personal medical information) or are visibly non-conforming they could put you in a camp.
ADHD? Camp. Trans? Camp. Homeless? Camp. Autism? Camp. Drug Use Disorder? Camp. Eating disorder? Camp. Look “abnormal”? Camp.
I don’t think really that a majority of the population is going to die. I do think significant numbers of deaths will happen around the equator at some point in the near future and spark a functionally unstoppable wave of immigration towards the earth’s poles. This will result in its own strife but again will only cause a small percentage of more of the population to die.
Thing’s will eventually stabilize as human civilization adapts and green energy and carbon capture take off. Most of the population will survive but almost everyone’s QoL will be NOTABLY worse by various conventional metrics. Though likely better in specific ways due to certain medical and automation advancements.
Expect birthrates to continue to drop globally however and the earth’s eco system will drastically change and become much less healthy. Most of existing humanity will cling to life though.