What has been studied, and with relatively simple maths involved, shows consistent humanitarian and economic benefits:

Investments in education and housing return between 5-12 times the initial budget back to the economy (GI Bill).

Universal basic income works. People still work. They start businesses. Or they engage in hobbies that build community (multiple pilot studies).

The solution for a lack of housing is giving people homes. This is less expensive than all the ER visits and policing involved in having people without housing around (one notable study, among others, in Finland).

Most medical research is publicly funded. Getting rid of pharmaceutical company profits does not harm medical research, it just returns benefits to the people who actually paid for it.

People who get welfare payments spend that money locally, providing more economic benefit to the community than a billionaire stashing profits in the Cayman Islands.