I just tested on my iPhone running iOS 18.5 and, on typing 'Trum" at the first of a sentence, iOS capitalizes it automatically and suggestions shows "Trump" with a capital "T":

However, "trump" was used as a verb or noun in the game of bridge long before the current POTUS was born. If I type "He played his trump card," I do not get the capitalized suggestion:

So I must assume that, when you type "trump" after "President," you won't get the capitalized auto-suggest. I tried typing "President miller" and "President chase" and did not the suggestion for the proper noun for either.
I do not see this as a manifesto or jab, but simply the expected outcome when a common verb or common noun is similar to a surname derived from another language†. Predictive text can't do every combo o f word and place of origin.
† — Ref: https://en.wikipedia.org/wiki/Trump_(surname)