What kind of evidence do you expect?

It’s impossible to give a static like “X % of former homeless let their apartment mold”. Or “X % of former homeless have trouble with hording”, “X % of former homeless end up with broken-in front doors”, etc. etc.

It’s not only unethical to build such a statistic, it’s also next to impossible because “former homeless” is not a countable group of people. And landlords wouldn’t even be allowed to collect that information.

The same goes for the number of people who choose to not go to organisations for help and don’t want to stay in the housing you offer them. These numbers can only be estimates. I can’t show you a proven number of people in this group, because it’s impossible to count these people.

If I tell you about my personal experiences, you will claim it doesn’t count.

When I tell you the reason the former step-by-step approach exists precisely because of the problems you get when you put people with severe problems into an apartment without further help, you will also claim that doesn’t count.

(Or that is what I assume because that’s what you wrote to another person who tried to tell you about these problems.)

You already have an opinion made up in your head it seems, and when people tell you what the struggles are in practicality, you build up a strawman that these people must just hate the homeless or something.

But these are real problems that really need to be addressed. Because otherwise you just cycle back to the beginning, where people already tried in the past to just put them under a roof in group homes and accomodations, expecting them to magically solve all their problems themselves. Then again think “let’s get them drug free / mentally healthier / out of debt first”, which also doesn’t work. And then you will be at the same point again where most countries are now.

The way to approach the problem is not to simply give homes to homeless people, you need a diverse range of systems in place to make it work.

If you don’t speak German, perhaps you can make an AI translation of this report: https://www.ssoar.info/ssoar/bitstream/handle/document/66376/ssoar-2018-steffen_et_al-Strategien_sozialraumlicher_Integration_von_Wohnungslosen.pdf?sequence=1&isAllowed=y&lnkname=ssoar-2018-steffen_et_al-Strategien_sozialraumlicher_Integration_von_Wohnungslosen.pdf

It describes, with multiple sources, what is necessary to make it work. For example with weekly visits to be able to step in when first signs of trouble with the housekeeping come up.