By definition, it is impossible for a single winner contest like the Presidency to be proportionally elected. Proportionality matters for multi-member bodies like legislatures or parliaments. I.e. 20% of the vote nets 20% of the seats. Single winner contests can only represent at best, half or more of the population when working well.

Winner take all (one winner): FPTP, single member district ranked ballots

Proportional (multiple winners): Party lists, MMP, multi-member district ranked ballots (STV)