The US uses a large patchwork of a multitude of smaller means tested programs. You frequently read about how people are telling each other about what programs one can apply to and how. In short becoming poor in the US means navigating a maze of small programs and understanding and having the energy to apply to all of these.
In a social democratic system most of these small means tested programs are replaced by large non-means tested programs. They aren't really programs but rather universal rights for everyone. There is much less to navigate.
1) Everybody gets heavily subsidized child care. There is nothing to apply for. Which reduces the economic burden of having children.
2) Health care while pregnant or anything related to children is completely free. For grownups you only pay small fees for doctors visits. You can't get into financial ruin over cancer treatment e.g.
3) Once you pay above a certain level for medication you don't pay anymore. There is a cost roof to the patient. Which prevents financial ruin due to medication. There is nothing to apply for or be eligible for. It just kicks in automatically.
4) If you are unemployed and struggle with getting a job, you get government aid to retrain or get new skills. It is not means tested.
5) Education is free and you get very favorable loans and stipends, everybody get the same regardless of income. It is only the conditions of the study which affects it. E.g. if you live away from home you get more than if you live at home. If you chose to study abroad you get more e.g. to cover tuition. E.g. I studied in the US and the Norwegian government payed most of the tuition. It means even if you are poor getting a decent education is not a major obstacle. You don't have to hunt for scholarships and spend weeks filling them out.
6) Sick pay and unemployment benefits are quite generous so you don't go to economic ruin because you get sick or unemployed for a while.
Of course some people do fall between the cracks in social democracy as well. But it takes a lot more effort to end up in poverty. More things need to go wrong. Typically the ones who end up on the street are drug addicts and alcoholics. But even most of them are offered accommodations.
However I still think universal basic income is worth exploring. Our system is by no means perfect. A significant problem is that because the welfare services are so generous, they are expensive and there is a lot of worry about abuse, especially from foreigners who have a more cynical view towards welfare programs because they have grown up in states where the common man in screwed over in every possible way. Exploiting the system then does not seem unfair. This lead to more monitoring and a harder push towards means testing and requiring certain actions by the recipient. They are very pushy on unemployed people e.g. They have to demonstrate that they are actively seeking work. If you are sick for longer periods you need meetings with a medical professional and the employer to come up with possible arrangements that could allow you to function at work.