Get your MIDI file into a notation editor properly: quantised into bars and exported as MusicXML that MuseScore, Finale, Sibelius and Dorico all open natively.
Most notation programs will open a MIDI file, and most make a poor job of it — you get raw timings written out literally, one voice per channel, and a page of tied notes nobody can read. The import dialog offers quantisation settings, but you are guessing at them before you can see the result.
Converting to MusicXML first does the interpretation up front and lets you look at it. You open a score that is already laid out on a grand staff with sensible note values, and spend your time on the musical corrections rather than fighting an import dialog.
MusicXML is a notation format: it stores clefs, key signatures, note spellings, beaming, lyrics and layout. MIDI stores none of that — it stores performance. So the conversion has to decide some things, and where the file is genuinely ambiguous we take the conventional reading rather than inventing detail.
The clearest example is enharmonic spelling. MIDI says "key 70"; notation has to write either A♯ or B♭, and only the musical context says which. Expect to correct a few of these in your editor — it is a limit of the source format, not of the converter.