Change source from
"osu!" -> "BOFU2017"
New RC rule only permits osu! as source if it was specifically originally made for osu. + "Website names may be used as sources when the song is tied to specific cultural phenomena related to the platform, or the song is composed as a website theme/background song."
Source for BOFU: https://www.youtube.com/watch?v=XtXRvEsWzQo
"BOFU2017" as the source is not very accurate since it doesn't fully state the website/event name as you mentioned in this case. I think using "BOFU2017 [THE BMS OF FIGHTERS ULTIMATE 2017] - LEGENDA EST A MYTH -“ is definitely more accurate. This can be paralleled with the case in which "SDVX6" is used as source instead of "SOUND VOLTEX EXCEED GEAR", for example.
Source: https://www.bmsoffighters.net/bofu2017/index_en.html
this was discussed in the BN server im pretty sure. the current source imo is a bit better since its a shortened version of what you pretty much said as that source is overly long than it honestly needs to be. there's no reason to have a source that long when it can be shorten and still be readable.
BOFU2017 would be a more true source than sdvx 6 however since it original came out for the event, and then licensed to konami respectively. would not mind having sdvx 6 in the tags tho.
u need some hitsound volume lines since the current hitnormal sounds super jank at some parts. copy and paste this into the [Timing Points] section in the .osu notepad (u can paste over whatever is in there currently) and make sure to apply this to every diff. should be good to go afterwards.
1360,343.662294518586,4,1,1,15,1,0
12357,-100,4,1,1,20,0,0
23354,-100,4,1,1,25,0,0
34351,-100,4,1,1,30,0,0
42599,-100,4,1,1,35,0,0
44661,-100,4,1,1,40,0,0
45348,-100,4,1,1,30,0,0
62188,-100,4,1,1,35,0,0
66655,-100,4,1,1,25,0,0
67343,-100,4,1,1,30,0,0
87962,-100,4,1,1,35,0,0
89853,-100,4,1,1,20,0,0
98960,-100,4,1,1,25,0,0
100334,-100,4,1,1,30,0,0
105833,-100,4,1,1,35,0,0
113565,-100,4,1,1,20,0,0
120954,-100,4,1,1,25,0,0
122329,-100,4,1,1,30,0,0
130577,-100,4,1,1,35,0,0
132638,-100,4,1,1,40,0,0
133326,-100,4,1,1,35,0,0
135560,-100,4,1,1,30,0,0
138824,-100,4,1,1,25,0,0
141574,-100,4,1,1,30,0,0
154031,-100,4,1,1,35,0,0
additional tags: KATASTROPHE Arcaea
KATASTROPHE is the genre it was dubbed for the BOFU contest and it's featured in Arcaea as well.