Homura is an instrumental song that Machiya brought to Wagakki band. The song has been played in many different versions. Beni Ninagawa on shamisen hates playing the song in its original version, so maybe she likes the quiet start of this version better. The last part is more similar to the original. The song has been with Wagakki band since the beginning but is still not on any of their seven studio albums.
Still recommending these two songs from daishinnenkai 2018
Wagakki Band - 戦-ikusa- + 拍手喝采 (Hakushu Kassai)/ Dai Shinnenkai 2018 Ashita e no Koukai [ENG SUB CC]

This is simply two ( of many ) versions of the same song - the first more traditional version of " Homura " played by Beni on the shamisen - the second rock  / jazz version is a variation on the song most people would recognise as " Homura "

To my taste, the Folk/Rock balance leaned far too much toward the rock side in the second half, with only the shamisen to counterbalance it.