Is the US considered a welfare state? If so, where would it be classified using the Esping-Andersen's welfare classification?
In Esping‐Andersen's The three worlds of welfare capitalism typology, the USA is classified as a "Liberal" welfare state (along with the UK, Australia, Canada and Ireland) and in contrast with the "Conservative" type (Finland, France, Germany, Japan) or the Social Democratic (Norway, Belgium, Denmark, Austria) (Source)
Esping Andersen is not using "Liberal" in the sense that it is used to describe more left-wing Democrats in the USA. It implies modest means-tested benefits, aimed mostly at the working class with strict entitlement rules, and considerable social stigma attached to receiving benefits.
It should be noted that the whole point of Esping-Andersen's welfare classification is to not look at welfare expenditure, which is/was the received method of classification. If we go by this more classical measure, which despite Esping-Andersen's viewpoint didn't go out of style with economists, the US scores somewhat below the OECD average, but not by a whole lot...
...but not so low if you consider the ACA (Obamacare) private health insurance as mandatory... (The large yellow sub-bar in the US case)
... which didn't last as mandatory for long during Trump's presidency.
Also of note, other post Esping-Andersen classifications that attempt to account for the healthcare dimension come a somewhat different picture, in which the US and the UK are similar on one dimension (the Esping-Andersen decommodification, basically), but quite different on the healthcare one (in the non-Obama US approach)...