Diminished playback when scores are posted to the MuseScore Web Page

I am in awe of the new orchestral sounds in MuseScore 4.0 and up. My playback at home gives me amazing feedback as to instrument sounds and possibility. However, when I have posted an mscz file to the MuseScore web page, all the sounds are off and the dynamics are wrong which makes the score almost unrecognizable from what I had created in my home set-up. Any advice for how I can post my scores and have them sound the same as I created them on the web page (or youtube for that matter)? My only recourse has been to create an mp3 and post to another music streaming site. I suspect that the web page does not have access to the new sound patches...