In this topic u/ erus and others already nicely explained how we know what we know about how the music sounded and also gave some examples for music from the 11th, 12th, 13th and 14th century.
I'm interested in the early middle ages, i.e. the 8th, 9th and 10th century, in particular Charlemagne the Great and Otto the Great.
Unfortunately it is difficult to answer the question much better than /u/azdac7 did in the post you linked. Before the 10th century, the surviving musical notation we have is not descriptive enough to include things such as tempo or inflection for us to have a complete understanding of how the music is suppose to be played or sung, instead we have to use our best guesses based on the relative melody and surviving church music from a period later than you are asking about. /u/erus explains this fairly well in his reply further down the thread you linked.
In answer to your question though, the best answer we can give you is that it would have sounded something like monophonic Gregorian plainchant for most of the period you are asking about (8th-9th centuries) followed by a harmonized polyphonic organum in the 9th to 10th centuries that more or less expanded on the plainchant basis to include multiple voices singing separate syllables and in some cases an extenuation of notes. I'm going to refer you to another previous post in this subreddit that you may have missed in your search, it is also more focused on the 11th to 14th centuries like the one you linked, but there is a larger variety of examples and a different perspective on the explanation of arrangements between /u/hhawks12 and /u/brushbender's two comments. In particular the first half of /u/brushbender's comment may be of particular interest to you, but unfortunately the two links in the beginning of his post are dead, so I've done my best to track down two alternative recordings for you, but remember, these are musical historians best guesses and may not be especially accurate, particularly on pacing. Moreover, these are very church-centric pieces that may have been modified for court purposes, especially in the latter half of the time period you are asking about.
Whole thread: https://www.reddit.com/r/AskHistorians/comments/xf4cc/how_accurate_is_the_music_that_we_hear_in/#header
brushbender's comment: https://www.reddit.com/r/AskHistorians/comments/xf4cc/how_accurate_is_the_music_that_we_hear_in/c5lvqd4/
Gregorian plainchant: https://www.youtube.com/watch?v=Fi5CZ3lTXP8
Early/free organum: https://www.youtube.com/watch?v=SgHzH5iDcGQ