Yes, in fact I'd say it's probably the easiest kind of modding for 6.
Assuming you have all
the DOA6 modding tools (warning: lots of NSFW ads, recommended you use an adblocker or browsers like Brave or Opera)
1. Use qrdbtool and extract SE_Common_BGM.srst and SE_Common_BGM.srsa from RRPreview.rdb
2. Drag the SRSA file onto SRSXtool.exe. This should create a folder of the same name wherever you extracted the SRST/SRSA files.
3. You can now replace any song in the game with any music you want. Only requirement is that they have to be in .ogg format (I recommend converting them using programs such as Audacity) and have the same name as another song file in the game in order to overwrite it. (something I did to understand the process was replacing another song in the game with For Your Existence, which only plays during the Nico fight in story mode as well as the credits (bgm_doa6_rtm_theme.ogg).
4. To make the changes work in game, drag the SRSA file again, but this time to SRSXtool_replace.bat. This will take every file in the BGM folder and replace the default music.
This should work. I may even potentially make a video tutorial if you need more