Poverty is relative, not absolute. Even if you gave everyone in the country $50,000 in UBI, you'd still have poverty, because you'd have people at the bottom of the income range who can't afford what others can.
The only way to possibly eradicate it is if you made everyone equal - same take home pay, no inheritance, no monetary gifts, etc. Everyone has the same net income at the end of the day.
That's.... just not true, and I feel like you don't really know what poverty is if you say that. Poverty is not just definitionally being in some lower percentile. Poverty is misery because you don't have financial power to meet your basic needs, or have to sacrifice all your time and comfort to do so. There's nothing relative about going hungry, living in bad housing with heat that doesn't work, working 2 jobs and sleeping 4 hours a night, etc.
your argument is so pedantic that it is insulting. it reminds me of Ben Shapiro's classic tweet [0] "Renewable energy: dumbest phrase since climate change. See the first law of thermodynamics, dumbass." You're like Ben Shapiro saying "eradicating poverty?? that's literally impossible... since poverty is defined as the lowest 5% of income and there will always be someone there. Learn percentiles, dumbass"