It's incredibly disappointing how long these issues have been endemic of the US welfare system. I'm not sure if other countries handle phase-outs more efficiently, but these would be painfully easy "bugs" to fix. It is within the power of these governments to address these issues -- they just don't care.
> While the median low-income American family may have a marginal tax rate of about 45%, there’s a large dispersion of experiences, depending on age, family size, location and benefits. Some families face an exaggerated problem -- 70% tax rates or occasionally much more. Just $1,000 in higher pay for a single mother in Oregon, in one example cited in Altig’s research, would result in a devastating loss of $15,000 in housing subsidies.
For further reading, Google "the poverty trap"
https://opentextbc.ca/principlesofeconomics/chapter/14-2-the....