By "Marxist" I'm assuming you mean Socialist.
The only two legislators I know who call themselves "Democratic Socialists" are AOC and Bernie. And, TBT, we could enact every supposed "socialist" program they are proposing and still be far less socialist than most of the countries of Western Europe (you know, the ones who are always listed as the happiest places on earth in the studies.)
When conservatives call a program like the Affordable Care Act--which is so tied to for-profit insurance and private industry it's nowhere near as affordable as it should be--"socialism," I almost think it would be like calling a bakery cake "dog food."
There is far too much labeling by people who know less than nothing about the product to believe that when a conservative calls Biden (let's say) a Socialist they know what they're talking about.
On the other hand, there are progressives who have called Trump a fascist. But read his interview with TIME Magazine (transcripts are available with direct quotes). They call him a fascist because when he describes his proposed policies and programs they are a pretty good match to what fascism actually is.