As far as I can tell the actual extremist right-wingers are on Gab rather than Twitter.
And I'm speaking from a US politics perspective, where Hillary Clinton is considered center-left. If we were to take a more international view, then Joe Biden is somewhere on the center-right, and Trump and Tucker are so far on the right that you can barely see the spaces between them and the nazis. For context, far-right Marine Le Pen of France is to the left of Tucker on most issues, except that she's a bit more openly racist.
Not saying all right winger are Nazis, but the "jews will not replace us" crowd definitely is. And the rest is at least authoritarian bordering facist. Same goes for some European parties: the AfD in Germamy, whateber LePen calls her outfit now in France, the current government party in Italy, the current politics of Nethanyahu (arguably not a Nazinof course, but a straight up authoritarian with religious tendencies and disdain for democratic seperation of powers), Hungary, the FPÖ in Austria... The list way too long.
Don’t underestimate the nationalist bloodlust.
Haven't some of them been clamouring for an attack on Mexico recently?
Anyway, there are worse figures than Tucker Carlson on Twitter. Some are outright nazis. Others can name them if they wish, but I won't amplify them here.