Megalomania is more than obsession with power. But even if this is what your definition is, this 100% would fit Trump. He was so obsessed with it, that he made claims about election fraud out of thin air and with no proof, after he learned that he lost. He also repeatedly mentioned a third term for him, should he have won the election 2020 or would win 2024. If that is not obsession with power, then what is?
One trait of megalomania would entail constantly talking about how great you are. Something Trump is not known for, or is he? ;-)
Promising to build a wall and have the other side pay for it does also fit the bill. Or fabricating stories how people would break in tears over their worship of you.
Or where did you hear that fairy tale that he made a fortune out of a measly one million dollar loan? It is lies he tells. Read it up. It is about half a billion that flowed from father to son over decades. The exact amount is hard to tell, because of all the fraud and obfuscation that was done. But that it was a million is a delibarate lie to look like a self made billionaire. It is understating the true amount by a factor of x100 to x1000.
Note, I am not exactly talking about how good or bad the candidates are. But I do talk about how you deny his megalomania. That you fell for his 1-million-dollar-loan boast lie is concerning. Please do not form your opinions on the basis of lies.