I think the combo colours are off, try choosing combo colours that fit with the BG, explore with grey-ish brown tones
with current hs u missing a lot of drums (00:45:500 - 00:46:166 - ) and main melody (00:44:666 - 00:45:000 - ) emphasize
small example of hs for this song https://www.dropbox.com/s/q3hxzyfewc2nca5/Camellia%20feat.%20Camellia%20-%20AREA%2052%20%28Cut%20Ver.%29%20%28flareling22%29%20%5Bhss%20exmp%5D.osu?dl=0
for main melody i used whistle with your sample 00:44:666 - 00:45:000 - 00:48:000 (1) - etc
for snare on 00:45:000 - clap to give drums emphasize aswell
for kicks just hitnormal sampleset 00:45:500 -
for some unique sounds i used 00:47:166 - soft + whistle or 00:48:832 (1) - normal + whistle
so u can focus on lead instrument that u follow and emphasize it with whistle and combine it with snare/kick if they exist there