That has been one of this dreams ever since he was installed in Oval Office the first time. He has been trying to become the "emperor" just as long. For example the chairman of the Joint Chiefs of Staff general Mark Milley described the last months of his first term by comparing it with the Nazis and the Reichstag Moment they pulled off, specially after Trump's goons attacked government buildings after the election and all the mess he caused back then...
Even recently a clip came out of him talking to the Zionist Zelensky and was fascinated about the idea of being able to remain in office even after the term ends, in case the country was at war!
Trump sees US national interests in absolute power and global domination, not in democracy (values). If he assumes full power without institutional restraint, America could truly transform into a Fourth Reich: a great, ultra-nationalist, exclusive, and authoritarian power in the 21st century. If Trump returns to power, the US could shift from liberal democracy to nationalist authoritarianism similar to 20th-century European fascism.
The issue of "Trump wants to make America a Fourth Reich" is a valid political metaphor. While Trump hasn't declared a new Reich, his personal characteristics (narcissistic, authoritarian, and admiration for dictators like Putin, Erdogan, and Kim Jong Un), nationalist-exclusionary policies, and efforts to undermine democratic institutions make comparisons with Nazi Germany (the Third Reich) relevant.
Furthermore, Donald Trump's leadership style is highly oriented toward self-branding, populism, and narcissism. International relations are viewed as a profit-and-loss proposition, not an ideology. His narratives of ultra-nationalism, anti-immigration, and law-and-order are reminiscent of classic fascist rhetoric. This rhetoric appeals to a conservative white voter base that feels threatened by globalization and the multicultural demographics of the US. Trump views extreme nationalist loyalty as a way to maintain "America First."