You're being either disingenuous or simply repeating talking points.
FDR and many other Democratic presidents have campaigned on and tried to create a robust universal healthcare plan. Congressional Republicans prevented it. Every time.
In FDRs second term, they told him the same thing. Then changed the rules so he couldn’t get a third.
If you're talking about the 22nd Amendment, limiting presidents to two terms in office, that happened after FDR was elected four times, and died in office midway through his fourth term. And it's yet another way to put a giant thumb on the scale in order to give regressionist shitheels more power than they should fairly command in US politics. (See also: Electoral College, Three-Fifths Compromise, the filibuster, gerrymandering.) Without that scale-tipping, US politics would be way more left now than it is.
You should be more informed on history before citing it to support your preconceived ideas.