Custom Drumset SoundFont (.sf2) Cuts Off Notes

This is technically about how to use Polyphone, HOWEVER: Everything seems fine on Polyphone's end, but when the SoundFont is imported into MuseScore 4, notes are not held for their proper amount of time (e.g. cymbals cut each other off, despite not being marked as an exclusive class in Polyphone; a cymbal sustains for about a quaver then cuts out for the next note, even if it isn't another of the same (or even a rest), which I would think is the only reason it could cut itself off).
What I'm asking is: How does one ensure that the samples sustain as they should when imported into MuseScore 4? I'm looking through Polyphone's Instrument table to look for settings, and none seem to fit the description I need. SOS.
P.S. If there's a link to which key number on a MIDI plays which drum/cymbal/sound, PLEASE do send it. I'm going off of a video https://www.youtube.com/watch?v=Oub2RBqDNZk but it seems to be for MuseScore 3, and some of the keys seem to not align with MuseScore 4.

Thank you.